Apportionment and Redistricting Following the 2020 Census

"Updated April 27, 2021

The census, apportionment, and congressional redistricting are interrelated processes that occur every decade. The U.S. Constitution provides that a decennial census determines the distribution of U.S. House seats across states. Dividing House seats across states is known as apportionment (or reapportionment). Each state must receive one House seat and additional seats are distributed proportionally based on state population size. States then engage in redistricting, creating or redrawing geographic subdivisions with relatively equal-sized populations for each House district.

Timelines for the census and apportionment are provided in federal statute and generally occur as scheduled every decade. The Coronavirus Disease 2019 (COVID-19) pandemic, however, affected 2020 census field operations and delivery of apportionment figures, and concerns remain about timing for the redistricting processes that follow. This Insight provides background on the typical timing of the census, apportionment, and redistricting, as well as a brief discussion of recent census operational changes and proposals, particularly those related to congressional apportionment and redistricting.

Typical Timing—Census, Apportionment, and Redistricting
 
Figure 1 illustrates a timeline of the typical census, apportionment, and redistricting processes. Federal statute requires that April 1 of any year ending in “0” marks the official decennial census date. A count known as the apportionment population, which reflects the total resident population in each state, is typically used to distribute House seats. Within nine months of the decennial census date (December 31 of the year ending in “0”), the Secretary of Commerce is to report the apportionment population to the President; the Census Bureau has often released apportionment counts publicly at about the same time.

According to this timeline, within the first week of the first regular session of the next Congress, the President transmits a statement to Congress with information on how to apportion House seats. The President’s message contains the apportionment population and resulting number of Representatives for each state, based on the total number of Representatives (435) and using the method of equal proportions.

The Clerk of the House sends each governor a certificate indicating a state’s number of Representatives within 15 calendar days of receiving the President’s apportionment message. Each state receives the number of Representatives noted in the President’s statement, beginning at the start of the next session of Congress (typically, early January of a year ending in “3”). States may then engage in their own redistricting processes before the start of that Congress, and the timing of redistricting varies based on state laws..."
Apportionment and Redistricting