Internal Boundaries

By the end of this lesson, students will be able to (per CED LO IMP-4.B, EK B.5):

• Define voting districts, redistricting, and gerrymandering and explain how each affects election results (per EK IMP-4.B.5).
• Identify the two main gerrymandering techniques: packing (concentrating opposing voters in few districts) and cracking (spreading opposing voters thinly across many).
• Apply Skill 5.A: identify the scales at which internal boundaries operate (state, county, city, neighborhood) and recognize that gerrymandering can occur at every electoral scale.
• Identify a contemporary example of partisan or racial gerrymandering with one specific district name.
• Explain the connection between internal boundaries (Topic 4.6) and the Modifiable Areal Unit Problem zoning effect (Topic 1.6).

Per CED EK IMP-4.B.5, "voting districts, redistricting, and gerrymandering affect election results at various scales." This is the only EK in Topic 4.6, but it covers a major contested area of contemporary politics with deep geographic content.

Voting districts

Voting districts are the geographic units within which voters elect representatives. In the United States, congressional districts elect members of the House of Representatives; state legislative districts elect state senators and representatives; city council wards elect city council members. Each district has a defined boundary, and voters within that boundary cast ballots for candidates competing for that district's seat.

Redistricting

Redistricting is the periodic redrawing of voting district boundaries to reflect population changes, usually after a census. In the US, redistricting happens every 10 years following the decennial census. The 14th Amendment "one person, one vote" principle (Reynolds v. Sims, 1964) requires districts within a state to have roughly equal population. Who controls the redistricting process largely determines the political outcome — state legislatures control most US redistricting; a few states (Iowa, California, Arizona) use independent commissions.

Gerrymandering

Gerrymandering is the deliberate manipulation of district boundaries to favor a particular party, candidate, or group. The term comes from a 1812 Massachusetts redistricting plan signed by Governor Elbridge Gerry that produced a salamander-shaped district. Gerrymandering uses two main techniques: packing (concentrating opposing voters into a few districts where they win by huge margins) and cracking (splitting opposing voters across many districts so they form minorities everywhere).

Connection to MAUP (Topic 1.6)

Gerrymandering is the political application of the Modifiable Areal Unit Problem zoning effect (covered in Topic 1.6). The same underlying voter distribution can produce wildly different election outcomes depending on how the districts are drawn. A state where voters are split 50-50 between two parties can be drawn to produce 8 of 10 seats for one party. The MAUP is not just a methodological abstraction — it is the foundation of partisan gerrymandering.

The two CED-relevant gerrymandering techniques. Memorize both names and how each works.

Modern partisan gerrymandering uses both techniques together: pack the opposing party's strongholds into a few districts they win overwhelmingly, then crack the rest of their voters across many districts they lose narrowly. The result is wildly disproportionate seat shares from roughly equal vote shares.

Four cases that show how internal boundaries shape elections.

United States · Congressional Gerrymandering

435 House districts · redrawn every 10 years

The US is the textbook gerrymandering case. State legislatures control most congressional redistricting. After the 2010 census, both parties drew aggressive partisan maps in states they controlled. North Carolina, Pennsylvania, Maryland, and others have produced congressional delegations with seat shares far different from statewide vote shares. Multiple Supreme Court cases (Rucho v. Common Cause, 2019) have left partisan gerrymandering largely a state-level issue.

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United Kingdom · Boundary Commissions

650 constituencies · redrawn by independent commissions

The UK uses independent Boundary Commissions (one per nation: England, Scotland, Wales, Northern Ireland) to redraw constituency boundaries. They prioritize equal population, geographic compactness, and respect for local government and community boundaries — partisan considerations are formally excluded. Result: comparatively little partisan gerrymandering by US standards, though boundary changes still affect outcomes.

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Australia · Independent Electoral Commission

151 House seats · AEC-managed redistribution

Australia's redistricting is done by the independent Australian Electoral Commission (AEC), which draws electoral boundaries based on population (within ±10% of state quota) and community of interest. Partisan considerations are explicitly excluded. The Australian system is often cited as a successful model for reducing gerrymandering.

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India · Delimitation Commission

543 Lok Sabha seats · delimitation frozen 1976-2026

India's constituency boundaries are set by an independent Delimitation Commission. To prevent population-growth disadvantages for southern states (which had lower fertility), India froze the number of seats per state in 1976. This freeze ends in 2026, with the next delimitation expected to substantially redistribute seats — one of the largest internal-boundary redistribution events anywhere.

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1. Per EK IMP-4.B.5, voting districts, redistricting, and gerrymandering affect election results at various scales. Pick one specific US state and identify how the 2010s gerrymander affected its congressional delegation's partisan composition compared to the statewide vote.
2. Distinguish packing from cracking. Why do partisan map-drawers usually use both techniques together rather than relying on just one?
3. The US, UK, and Australia all elect representatives from geographic districts. Why does the US have so much more partisan gerrymandering than the UK or Australia? What institutional features matter?
4. Racial gerrymandering (drawing districts to dilute minority voting power) and partisan gerrymandering (drawing districts to favor a party) are legally treated differently in the US. Should they be? What is the geographic distinction, and what is the political distinction?
5. Connect Topic 4.6 to Topic 1.6 (the Modifiable Areal Unit Problem). Gerrymandering is the political application of which MAUP component (scale effect or zoning effect)? Why?

Draft alignment — pending educator review. AP HG codes correspond to the official College Board Course and Exam Description (Effective Fall 2020, V.1). Statements below are paraphrased in CountryReports' own voice; refer to the College Board's published CED for verbatim wording.

AP® and Advanced Placement® are registered trademarks of the College Board. The College Board was not involved in the production of this material and does not endorse it. Standards statements above are paraphrased; codes refer back to the official College Board CED, the NCSS C3 Framework, the Common Core State Standards, and other cited frameworks.