How is the number of seats in the US House apportioned by state?

1. How seats are allocated: the constitutional baseline and the method used

The Constitution establishes proportional representation in the House and guarantees each state at least one representative; beyond that baseline Congress and statutes determine how to divide the remaining seats based on population totals from the decennial census ^{[1] [2]}. Since 1941 Congress has used the Huntington–Hill method, commonly called the “method of equal proportions,” to compute which states get which of the 435 seats; that algorithm assigns seats by computing priority values so that states receive additional seats in order of those values until all 435 seats are allocated ^{[2] [3]}.

2. Where the population numbers come from and timing of apportionment

Apportionment uses the decennial census population counts produced by the U.S. Census Bureau; the apportionment population from each census determines representation for the next decade ^[5]. After the President transmits census results to Congress, federal law requires the Clerk of the House to notify each state government of its apportioned number of seats (the statute sets a deadline no later than January 25 after the census) ^{[3] [4]}.

3. What happens after states learn their seat totals

Once the Clerk tells governors how many seats each state is entitled to, state legislatures are responsible for redrawing congressional district lines (or in some states independent commissions do the mapmaking) so that the state’s allocated seats are translated into districts for elections; note that apportionments take effect two Congresses (three years) after the census, allowing time for redistricting and implementation ^[4].

4. Fixed size of the House and historical context

The House currently uses a fixed total of 435 voting members for the 50 states; that total has been in law since the Reapportionment Act of 1929, with temporary exceptions when Alaska and Hawaii were admitted, and the decision to fix the size means apportionment is a zero-sum exercise — one state’s gain is another’s loss ^{[3] [2]}. Efforts to change the size (for example, the long-unratified Congressional Apportionment Amendment from the 18th century proposing a different formula) exist in historical record but were never adopted ^[6].

5. Practical tools and explanations of the calculation

State-level guides and legislative offices commonly explain the calculation by describing “priority values” or the n-based sequence used in Huntington–Hill; several public tools and state explanations demonstrate the priority-value ranking and how adding seats changes a state’s next priority ^{[7] [8]}. The House Historian’s pages provide background on the different methods Congress has used over time and why equal-proportions was adopted ^[2].

6. Political and institutional implications

Because apportionment links House seats to census counts, population shifts across states can change political power in the House and, through the Electoral College formula, presidential electors as well — the decennial apportionment therefore affects both congressional representation and a state’s electoral vote totals ^{[3] [5]}. After apportionment, political actors — state legislatures, governors, and sometimes independent commissions — influence the shape of districts; that makes redistricting a consequential follow-up to the technical apportionment step ^[4].

7. What the supplied sources do not address

Available sources do not mention detailed step‑by‑step arithmetic examples of the Huntington–Hill calculation in this packet, nor do they provide state-by-state apportionment tables for the most recent census within these search snippets — those specifics are typically published by the Census Bureau or on apportionment calculators ^{[8] [5]}. Also not found in current reporting here: discussion of alternative reform proposals in active contemporary legislative debate beyond historical amendments ^[6].

Taken together, the official process is straightforward in principle: the decennial census yields population counts, the Huntington–Hill method ranks priority values to distribute the fixed 435 seats, the House Clerk informs states, and state authorities redraw districts — a technical mathematical allocation with clear political consequences ^{[1] [2] [4]}.