How Singapore’s Electoral Boundaries Are Drawn

An electoral map looks final only after it has been published.

Before that moment, it is the output of a chain: people move, new housing is completed, old estates change, electoral registers are updated, population differences emerge, a review committee is appointed, technical recommendations are made, the Government decides whether to accept them, and the legal boundaries are then specified through the machinery of election law.

That chain matters because a constituency is not simply a neighbourhood name. It is a legal electoral division. It determines which electors vote together, how many Members of Parliament are returned from that division, whether it is a Single Member Constituency or Group Representation Constituency, which polling districts sit inside it and which candidate or group of candidates an elector may choose at a parliamentary election.

Singapore’s Electoral Boundaries Review Committee, usually called the EBRC, sits in the middle of this process. It is highly visible when a General Election approaches, but the Committee itself is not the whole legal mechanism. The EBRC reviews and recommends. The Government receives the report. Election law supplies the formal route by which electoral divisions are specified. Maps, Gazette instruments, polling districts and the Registers of Electors then make the recommendation operational.

Quick answer: who draws Singapore’s electoral boundaries?

The practical answer has several parts.

The Prime Minister appoints the Electoral Boundaries Review Committee as a matter of established practice.
The EBRC comprises senior civil servants with technical responsibilities relevant to population, housing, land, statistics and elections.
The Committee works from terms of reference and current electoral-register data, taking account of population shifts and housing developments.
The Committee recommends the number and boundaries of SMCs and GRCs and explains the main rationale in a report.
The report is presented publicly as a White Paper after the Government accepts the recommendations.
Under section 8 of the Parliamentary Elections Act, electoral divisions are formally specified by notification in the Gazette, with boundaries capable of being defined through coordinates, descriptions, maps or images.
The Elections Department publishes maps and electoral information so electors, parties and candidates can identify the operative divisions.

So the most accurate sentence is not simply “the EBRC draws the map”. The EBRC is the technical recommending body inside a larger constitutional, administrative and statutory chain.

1. Why electoral boundaries need to change at all

People do not remain evenly distributed across Singapore.

A new town can add tens of thousands of residents. A mature estate can age and shrink in household size. New Build-To-Order projects can fill land that previously had few electors. A redevelopment programme can alter population density. Private housing can expand. People move between districts. Citizenship changes the electorate differently from total resident population. The electoral register therefore changes even when the physical island does not.

If constituency boundaries never moved, some Members of Parliament could eventually represent far more electors than others simply because development was uneven. The 2025 EBRC report illustrates this problem directly. It recorded 2,753,226 electors in the Provisional Registers as at 1 February 2025, an increase of 101,791 from the 2,651,435 electors used as the GE2020 reference. The growth was not evenly distributed. The report singled out divisions such as Pasir Ris-Punggol, Sembawang, Tampines, Hong Kah North and Potong Pasir as places affected by comparatively strong growth or new housing.

Boundary review is therefore partly an exercise in keeping representation usable as the population map changes.

2. The EBRC is not a permanent second election commission

The EBRC is convened for a review ahead of a future election rather than operating continuously as a standing public body that redraws constituencies every year. Elections Department guidance says electoral boundaries are generally reviewed just before each General Election so that an updated set of boundaries can be used.

This timing explains why the formation of the Committee is politically significant. Once an EBRC is convened, Singapore has entered a preparatory stage in which the electoral map may change, although the Committee’s appointment does not itself announce an election date.

The distinction is useful: review of boundaries, dissolution of Parliament, issuance of the Writ of Election, Nomination Day and Polling Day are separate events in the election sequence.

3. Who sits on the Committee

ELD’s public election guidance describes the EBRC as comprising senior civil servants who hold positions connected to the technical information needed for boundary review. The stated composition includes the Secretary to the Prime Minister as chairperson, the Chief Executive Officer of the Housing & Development Board, the Chief Executive of the Singapore Land Authority, the Chief Statistician, and the Head of the Elections Department as secretary.

That composition tells us what kind of problem boundary review is treated as administratively.

HDB knows where major housing growth is occurring.
SLA works with land, cadastral and geographical information.
The Department of Statistics understands population structure and official statistical geography.
ELD understands polling districts, electoral registers and election administration.
The Prime Minister’s Office provides the chairing link to the appointment and terms of reference.

The map is therefore treated as a cross-agency technical object, not merely a set of lines drawn by one cartographer.

4. The terms of reference are the Committee’s operating brief

The EBRC does not begin with an unlimited instruction to redesign Singapore however it wishes. It receives terms of reference.

For the 2025 review, the Committee was asked to review existing electoral boundaries and recommend the number and boundaries of GRCs and SMCs based on the number of electors in the latest Registers of Electors. It was specifically told to consider significant changes in elector numbers caused by population shifts and housing developments.

The Committee was also asked, in determining the number and size of GRCs and SMCs, to keep three broad parameters at about the same level as the previous General Election: the average size of GRCs, the proportion of MPs elected from SMCs, and the average ratio of electors to elected MPs.

Those instructions are important because they reveal what the Committee is trying to stabilise while allowing individual boundaries to move.

5. A boundary review is not simply a quest for identical constituency populations

A common mental model is that constituency drawing works by taking Singapore’s electorate, dividing it by the number of MPs, and then forcing every electoral division to contain exactly that number of electors per MP.

The 2025 report shows a more practical approach. The GE2020 reference ratio was 28,510 electors per elected MP. The Committee used this as a guide rather than as a rigid mathematical command. A 4-member GRC at that ratio would contain roughly 114,000 electors and a 5-member GRC roughly 143,000. Yet actual constituencies differ because the map also has to deal with real housing estates, roads, future growth, existing polling districts and the need to form workable electoral divisions.

The Committee’s final 2025 recommendations produced an average of 28,384 electors per elected MP across the proposed map. The number is close to the earlier reference, but the individual divisions are not clones of one another.

6. Polling districts are the smaller pieces from which larger divisions can be assembled

An electoral division is not redrawn by moving individual voters one household at a time. Singapore’s election administration uses polling districts as smaller geographic units. The EBRC report often describes changes by identifying polling districts that move from one division to another or are combined to form a new division.

This matters because it makes the map operational. Polling districts can be linked to electoral registers, polling stations and local geography. When the larger constituency changes, the smaller units provide a way to reconstruct which electors belong where.

Think of an electoral division as a larger shape assembled from smaller registered pieces. The review changes the grouping. Election administration then uses the resulting configuration to determine where people vote and which contest they participate in.

7. The 2025 report shows three main kinds of boundary change

The 2025 EBRC grouped its recommendations into three broad categories. That classification is useful because it shows that not every changed line has the same cause.

First, direct responses to significant growth. Rapidly growing divisions can become too large relative to the review parameters. The Committee responded by carving out new SMCs or creating new GRC configurations around areas of strong development.

Second, consequential changes. Once one boundary moves, neighbouring divisions may also need adjustment. A change in Punggol, for example, affects what remains of the surrounding Pasir Ris area. Rebalancing one district can therefore propagate into adjacent districts.

Third, minor regularisation or no change. Some boundaries can be aligned to clearer geographic features, while some constituencies remain stable because the case for change is weaker.

This is a network problem. Moving one line can force another line to move because the island must still be completely partitioned into electoral divisions with no elector left outside the system.

8. Punggol is a useful example of population growth becoming electoral geography

In 2025, Pasir Ris-Punggol GRC had experienced the largest increase in electors since GE2020 and was expected to continue growing with new housing. The Committee recommended carving out the Punggol estates from Pasir Ris-Punggol GRC and merging them with Punggol West SMC to form a new 4-member Punggol GRC.

The report also noted that this configuration better reflected the identity of estates in Punggol town.

Notice the two kinds of reasoning in the same change. One is numerical and forward-looking: strong elector growth. The other is geographical and social: the coherence of a town identity. Electoral boundaries are therefore not merely arithmetic containers. They also interact with recognisable urban places.

9. Tengah shows why future housing matters before every flat is occupied

Hong Kah North SMC had grown significantly and was expected to continue growing rapidly because of new housing in Tengah and Bukit Batok West. The 2025 Committee concluded that it had become too large to remain an SMC.

The response was not simply to split the SMC in half. The Tengah estates were recommended for absorption into Chua Chu Kang GRC. To keep Chua Chu Kang as a 4-member GRC while making room for future Tengah growth, Bukit Gombak and Hillview estates were carved out to form a new Bukit Gombak SMC.

This is a good example of anticipatory geography. Boundary review is not only a snapshot of today’s electorate. Housing development gives the Committee evidence about where tomorrow’s electorate is likely to grow.

10. Consequential changes reveal why electoral maps behave like connected systems

Suppose a rapidly growing district is carved out of a GRC to form a new constituency. The remainder may now be too small, oddly shaped or no longer aligned with the intended GRC size. That remainder may need to merge with adjacent polling districts. Those adjacent divisions then change too.

The 2025 report contains several such chains. The creation of Punggol GRC affected the remaining Pasir Ris estates, which were combined with nearby East Coast polling districts to form Pasir Ris-Changi GRC. East Coast then took in adjacent districts from Marine Parade. Changes around Potong Pasir, MacPherson and Mountbatten contributed to a reconfigured Marine Parade-Braddell Heights GRC.

One change creates another because there is no empty electoral space between constituencies. The whole map must still fit together.

11. Geographic features can become useful legal edges

A boundary is easier to understand when it follows a recognisable road, river, railway corridor or other stable feature. The 2025 report describes efforts to regularise selected boundaries along key geographical features.

One example involved new HDB developments at Rail Green in Choa Chu Kang. The older electoral boundary followed a former railway alignment that no longer existed as a working railway. The Committee recommended realigning the boundary along Woodlands Road, assigning the new estates coherently to Chua Chu Kang GRC.

This reveals another practical constraint: a legal line can outlive the physical feature that once made it intuitive. Periodic review lets the electoral map catch up with a changed city.

12. Naming is part of electoral legibility

Constituency names do not determine legal boundaries, but they help people understand the geographic object those boundaries create. The 2025 Committee continued the use of double-barrelled names for some GRCs where more than one recognisable area was represented in the configuration, including Jurong East-Bukit Batok, Pasir Ris-Changi and West Coast-Jurong West.

Marine Parade GRC was also renamed Marine Parade-Braddell Heights GRC.

A name therefore performs a communication job. It gives residents and candidates a shorthand for a complex boundary made from many polling districts. But the name should never be mistaken for the boundary itself. Two people can live in neighbourhoods associated with the same everyday place name while belonging to different electoral divisions depending on the actual gazetted line.

13. “Hougang” demonstrates why place, planning and constituency must be separated

Singaporeans use place names at several scales. Hougang can refer to an HDB town, a planning area, neighbourhoods around Kovan and Upper Serangoon, or the Hougang Single Member Constituency. Those objects overlap but do not have identical boundaries.

The same is true elsewhere. A resident may say “I live in Tampines” in everyday geographic terms while the electoral question is more specific: which electoral division and polling district contains the registered address?

This is why ELD provides a postal-code lookup and official electoral maps. Electoral membership is determined by the operative election geography, not by colloquial neighbourhood identity.

14. The EBRC report is a recommendation document, not the Gazette itself

The EBRC report is extremely important because it explains the proposed map and the principal reasons for major changes. But the report should be distinguished from the legal instrument that specifies electoral divisions.

Section 8 of the Parliamentary Elections Act provides that the Minister may, by notification in the Gazette, specify the names and boundaries of Singapore’s electoral divisions. The Act permits boundaries to be described using measurements, bounds, coordinates or maps and images with sufficient markings.

This gives the process a clean legal handoff:

technical recommendation → Government acceptance → statutory specification → operational election map.

A researcher should know which stage a document belongs to before treating it as legally final.

15. Maps are not decorative; they are part of the evidence trail

Modern boundary law has to be geographically precise. Since amendments that took effect in 2024, the Parliamentary Elections Act expressly accommodates the use of maps or images in specifying electoral boundaries and requires arrangements for larger certified maps to be available for public inspection where relevant.

ELD publishes electoral maps and allows electoral boundaries to be viewed through OneMap. This matters because a prose description such as “east of this road and south of that canal” can become difficult to use in dense urban environments. A mapped boundary makes the legal geography inspectable.

The strongest evidence trail therefore combines text and geography: Gazette instrument, official map, polling-district composition and elector lookup.

16. The Committee says it does not use past election results or voter profiles to draw new boundaries

Because electoral boundaries can affect political competition, one of the most important questions is what information the EBRC says it uses.

ELD’s election FAQ states that the Committee takes into account population shifts and new housing developments and that it does not examine the results of past elections or the profile of voters when delineating new boundaries.

This is an official description of the Committee’s method and should be reported as such. It is also useful to separate this factual statement from wider political debates about electoral-boundary governance. A reader can acknowledge the published methodology, inspect the report and maps, and separately evaluate arguments about whether Singapore should adopt a different institutional model for future boundary reviews.

17. Transparency has more than one layer

People sometimes ask whether electoral boundary drawing is “transparent” as though transparency were a single yes-or-no property. It is more useful to identify the layers of information that are public and the layers that are not published in the same resolution.

Public materials include the Committee’s terms of reference, membership structure, final report, high-level rationale for principal changes, electoral division maps, elector counts, polling-district composition and the legal Gazette instruments.

The Committee does not publish a transcript of every internal technical discussion or a line-by-line deliberative record for every possible alternative boundary. Government responses in Parliament have stated that the EBRC should be allowed to work professionally without overly prescriptive requirements and that explaining the technicalities of every individual change is not considered practicable.

A precise description therefore avoids both extremes: the process is not undocumented, but neither is every internal decision path exposed as a public deliberative dataset.

18. The Government’s acceptance matters

The 2025 White Paper states that the Prime Minister received the EBRC report on 7 March 2025 and that the Government accepted the Committee’s recommendations. The report was released publicly on 11 March 2025 and the recommended 33 electoral divisions were implemented for the next General Election.

This sequence distinguishes recommendation from executive acceptance. The Committee is not a legislature and does not itself dissolve Parliament, issue the election writ or conduct the poll. Its task is narrower: review and recommend the electoral geography.

The map then travels into the election system through the legal mechanisms that make those electoral divisions operative.

19. The 2025 map: 33 divisions and 97 elected MPs

The 2025 EBRC recommended 33 electoral divisions: 15 SMCs and 18 GRCs. Together they returned 97 elected Members of Parliament.

The GRCs comprised eight 4-member GRCs and ten 5-member GRCs. The final structure produced an average GRC size of 4.56 MPs, an SMC share of 15.5% of elected MPs, and an average of 28,384 electors per elected MP based on the Committee’s reference data.

Those numbers are useful not because they define a permanent constitutional optimum, but because they show how the Committee translated its terms of reference into a measurable end state for that particular review.

20. SMC and GRC design is a separate legal question from the shape of individual boundaries

Boundary review determines how the island is divided. The SMC/GRC system determines how representation is structured within those divisions.

An SMC returns one elected MP. A GRC returns a group of MPs, with statutory and constitutional provisions designed to ensure minority representation. The EBRC’s terms of reference therefore ask it not only where lines should be drawn, but also how many divisions should be SMCs or GRCs and how large the GRC groups should be.

These are connected decisions, but not identical ones. A boundary can shift without changing the electoral system. A GRC can remain a GRC while some polling districts move. An SMC can be newly created from part of a larger division. Keeping the two questions separate makes the map easier to understand.

21. Boundary review affects candidates as well as voters

When a boundary changes, residents may find themselves voting in a different electoral division even though they have not moved home. Political parties may need to reorganise which teams contest which districts. Prospective candidates may have to learn a new constituency configuration. Campaign plans, walkabout routes, polling agents and counting arrangements all depend on the final electoral map.

This is why the interval between publication of the EBRC report and the election matters operationally. ELD has stated that, as with past elections, there will be sufficient time after release of the report for candidates and parties to prepare.

But the deeper point is that electoral geography is infrastructure for the election. Every later process depends on it.

22. Boundary changes do not mean residents have physically moved

When an estate moves from one constituency to another, nothing about the resident’s address has changed. What changes is the political grouping attached to that address for the purpose of parliamentary elections.

This is an important conceptual distinction. Administrative geography consists of many overlapping maps: planning areas, postal sectors, HDB towns, school zones, police divisions, municipal boundaries and electoral divisions. A change in one does not automatically rewrite the others.

Electoral boundaries are therefore one projection of Singapore, built for one specific job: organising representation and voting.

23. How an elector can verify the current constituency

The most reliable route is not to infer the constituency from the nearest MRT station, town name or a campaign poster. Use the official election lookup based on the registered address and postal code.

ELD publishes electoral boundaries, maps and voter services. OneMap can also display the electoral boundary layer. During an election, the poll card and voter services identify the allotted polling station.

This matters especially near constituency edges, where two blocks across a road from one another may belong to different electoral divisions.

24. How a researcher can reconstruct a boundary change

For a robust evidence trail, work in chronological order:

Open the previous EBRC report and map.
Open the latest Registers-of-Electors figures used by the Committee.
Read the latest terms of reference.
Read the Committee’s explanation of major growth areas and consequential changes.
Compare the old and proposed polling-district composition.
Open the White Paper showing Government acceptance.
Check the Gazette instruments that specify the final electoral divisions.
Open the official electoral maps.
Check ELD’s constituency and elector lookup for operational confirmation.

This sequence is more reliable than reconstructing the map from newspaper graphics alone, because every step can be tied to an official source.

25. Common misconceptions

Misconception: Constituency boundaries follow town boundaries.
Not necessarily. Electoral divisions are designed for elections and may cross, divide or combine areas that people regard as separate towns or neighbourhoods.

Misconception: The EBRC’s report itself is the legal Gazette notification.
No. The report recommends. The Parliamentary Elections Act provides the statutory route by which electoral divisions are specified.

Misconception: Every constituency must contain exactly the same number of electors.
The Committee works with population and representation parameters, but actual divisions are shaped by geography, polling districts, growth and the SMC/GRC structure.

Misconception: The Committee says it uses past results to make constituencies politically competitive.
ELD’s official FAQ states that the EBRC does not examine past election results or voter profiles when delineating new boundaries.

Misconception: Formation of the EBRC means Polling Day has been announced.
No. Boundary review is one preparatory stage. Dissolution, the Writ, nomination and polling follow separate legal steps.

26. A boundary map is a time-stamped object

Electoral maps should always be read with a date. A boundary used at GE2020 may not be the boundary used at GE2025. A constituency name may survive while its internal composition changes. A new SMC may appear. A former SMC may be absorbed. A GRC may be renamed.

This makes historical election analysis inherently versioned. If you are studying how a resident voted in a past election, use the map and register structure from that election, not today’s map.

The same rule applies to news archives. A statement that “this estate is in Constituency X” may have been perfectly accurate when written and wrong after the next boundary review.

27. What the electoral map can tell us — and what it cannot

An official map can tell us the legal location of a boundary, the electoral division containing an address, the polling districts grouped together and the scale of the constituency.

It cannot by itself tell us why voters choose a party, whether an MP represents residents effectively, whether a campaign is persuasive or how political identity forms. Those are different questions requiring different evidence.

This boundary discipline is important. A map is evidence about geography. It should not be made to carry claims about political behaviour that the map does not contain.

28. Why this matters beyond elections

Electoral boundaries are one of the clearest examples of how Singapore converts a changing physical city into an administrative system.

Housing policy changes where people live. Transport changes accessibility. Land planning changes density. Demographic change alters the electorate. Election administration then has to redraw a representation map on top of those deeper urban changes.

That is why a new BTO precinct can eventually affect electoral geography even though housing policy and electoral policy are institutionally different. Systems connect through consequences. One agency builds homes; population shifts; the register changes; the electoral map later adapts.

29. The deeper idea: electoral boundaries are an interface between people and representation

A constituency line is invisible on the ground. There is no wall along most electoral boundaries. People cross them every day without noticing. Yet during an election, that invisible line decides which ballot contest a voter enters.

That makes the electoral map a powerful interface. It translates millions of individual registered addresses into a finite set of representative contests. The map has to be geographically complete, administratively workable and legally legible. It also has to be capable of changing because the city beneath it changes.

The EBRC is therefore best understood not as a mysterious map-making event but as one stage in a recurring update cycle:

population and housing change → electoral registers change → technical review → recommendations → Government acceptance → Gazette specification → maps and polling districts → election → representation.

Once that chain is visible, the right question is no longer simply, “Who drew this boundary?” The better question is: what population change triggered review, what terms guided the EBRC, which polling districts moved, what rationale was published, how was the recommendation given legal effect, and which dated map proves where the boundary actually lies?

How Singapore’s Electoral Boundaries Are Drawn | The EBRC, Constituencies and the Published Evidence Trail