The distribution of seats in Congress is called congressional apportionment. It is the system that determines how many congressional seats each state is allocated. Congressional apportionment in the House of Representatives is based on each state’s population. In the Senate, congressional apportionment works differently because each state is guaranteed two Senate seats, regardless of its population.

Reapportionment and the Census

Every 10 years, using census results, America’s 435 seats in the House of Representatives undergo the process of reapportionment. This is necessary since states’ populations are in a constant state of fluctuation due to births, deaths and relocations. During the process of reapportionment, states gain, lose or retain the same number of seats they had prior to the census. However, regardless of population, every state is entitled to at least one seat in the House of Representatives.

States and Electoral Boundaries

While the federal government determines the number of House seats a state is allocated, it is up to each state to draw the lines of their congressional districts. States determine, based on population distribution, where voting boundaries are located. To encourage fairness, every United States citizen has the right to contest how a state determines these boundaries.

Apportionment in the Senate

Every state is constitutionally guaranteed two Senate seats. Unlike in the House of Representatives, the census has no bearing on the Senate’s 100 seats. Each state retains its two Senate seats regardless of population changes.