Explanation:
United States congressional apportionment is the process[1] by which seats in the United States House of Representatives are distributed among the 50 states according to the most recent decennial census mandated by the United States Constitution. Each state is apportioned a number of seats which approximately corresponds to its share of the aggregate population of the 50 states.[2] However, every state is constitutionally guaranteed at least one seat.

Allocation of congressional districts in the House of Representatives after the 2010 U.S. Census

Allocation of congressional districts after the 2000 U.S. Census

The 435 seats of the House grouped by state (post-2010 Census reapportionment)
The number of voting seats in the House of Representatives has been 435 since 1913, capped at that number by the Reapportionment Act of 1929—except for a temporary (1959–1962) increase to 437 when Alaska and Hawaii were admitted into the Union.[3] The Huntington–Hill method of equal proportions has been used to distribute the seats among the states since the 1940 census reapportionment.[1][4] Federal law requires the Clerk of the United States House of Representatives to notify each state government of the number of seats apportioned to the state no later than January 25 of the year immediately following each decennial census.
The size of a state's total congressional delegation (which in addition to representative(s) includes 2 senators for each state) also determines the size of its representation in the U.S. Electoral College, which elects the U.S. president.