Apportionment is the process of dividing the 435 memberships, or seats, in the U.S. House of Representatives among the 50 states based on the apportionment population counts from the decennial census.

The apportionment population count for each of the 50 states includes the state’s total resident population plus a count of the overseas federal employees (and their dependents living with them overseas) who have that state listed as their home state in their employers’ administrative records.

The resident population counts include all people (citizens and noncitizens) who are living in the United States at the time of the census. People are counted at their usual residence, which is the place where they live and sleep most of the time.

The resident population also includes military and civilian employees of the U.S. government who are deployed outside the United States (while stationed or assigned in the United States) and can be allocated to a usual residence address in the United States based on administrative records from the Department of Defense.

The resident population counts for the District of Columbia, Puerto Rico, and the U.S. Island Areas are not included in apportionment calculations (because those areas do not have voting seats in the U.S. House of Representatives), but they are included in other data products.

Note: The resident population counts are available down to the lowest levels of geography (i.e. census block), but only the state totals are used for apportionment. The more detailed resident population data are included in other census data products that are used for redistricting and many other purposes.

The counts of overseas federal employees include military and civilian employees of the U.S. government who are stationed or assigned outside the 50 states (and the District of Columbia) and their dependents living with them overseas. The counts also include U.S. military personnel assigned to U.S. military vessels that have a homeport outside the 50 states.

Also, some people who are deployed outside the United States (while stationed or assigned in United States) cannot be included in the resident population because administrative records are insufficient to allocate them to a usual residence address in the United States. In those cases, the Census Bureau will use administrative records from the Department of Defense to allocate them to their home state and include them in the counts of overseas federal employees.

The counts exclude any overseas federal employees who cannot be successfully allocated back to their home state based on their employers’ administrative records. The counts also exclude private U.S. citizens living overseas who are not employed by the U.S. government.

Note: The counts of overseas federal employees are only available as state totals, and they are only used for apportionment. They are not included in any other census data products, and they are not used for redistricting.

Agencies and departments of the U.S. government provide the Census Bureau with counts of their overseas employees (and their dependents living with them overseas) by their home state based on their administrative records.

Yes, all people (citizens and noncitizens) with a usual residence in the United States are included in the resident population for the census.

Yes, all people of all ages (even newborn babies) with a usual residence in the United States are included in the resident population for the census. Being registered or eligible to vote is not a requirement for inclusion in the resident population counts.

Article I, Section 2 of the U.S. Constitution mandates that an apportionment of representatives among the states be carried out within every 10-year period.

The apportionment of seats in the U.S. House of Representatives is calculated every ten years using the method of equal proportions, according to the provisions of Title 2, U.S. Code. Congress decides the method used to calculate the apportionment. This method has been used in every census since the 1940 Census. The method computes "priority values" based on each state's apportionment population.

Based on the 2020 Census, the average number of people per representative in the U.S. House of Representatives is 761,169. This is an increase of 50,402 (7.1%) compared with the average of 710,767 people per representative based on the 2010 Census.

Title 13, U.S. Code requires that the apportionment population counts for each state be delivered to the President within 9 months of the census date, and it requires that the census date is April 1 of the census year. This means that the statutory deadline for delivering the counts to the President is December 31 of the census year. Amid COVID-19-related delays in data collection and data processing, the Census Bureau will deliver the apportionment population counts as close to the statutory deadline as possible.

According to Title 2, U.S. Code, within one week of the opening of the next session of the Congress in the new year, the President must report to the Clerk of the U.S. House of Representatives the apportionment population counts for each state and the number of representatives to which each state is entitled.

Also according to Title 2, U.S. Code, within 15 days of receiving the apportionment population counts from the President, the Clerk of the House must inform each state governor of the number of representatives to which each state is entitled.

Amid COVID-19-related delays in data collection and data processing, the Census Bureau will deliver the apportionment population counts as close as possible to the statutory deadline of December 31, 2020. When the counts are delivered to the President, they will also be disseminated to the public through a press release on the Internet.

Apportionment is the process of determining the number of representatives to which each state is entitled in the U.S. House of Representatives based on the decennial census.

Redistricting is the process of revising the geographic boundaries of areas from which people elect representatives to the U.S. House of Representatives, a state legislature, a county or city council, a school board, etc.