Summary

Every decade, the apportionment (or reapportionment) process determines the distribution of U.S. House seats across states. The Constitution requires a U.S. population count every 10 years (the federal decennial census) in order to distribute House seats based on each state’s population. Once the census and apportionment are complete, states then engage in redistricting to create or redraw geographic subdivisions for each House district and for their own state legislatures. Data delivery delays following the 2020 Census raised some concerns about possible effects on the ability of states to conduct redistricting ahead of the next election cycle. For example, the condensed timeline may have presented challenges for states to complete congressional redistricting by constitutional or statutory redistricting deadlines, candidate filing deadlines, or primary election dates. Each state with multiple congressional districts has completed its initial redistricting process and many states did so ahead of those related dates, although not without difficulties in at least some states. Enacting an initial redistricting plan, however, does not necessarily mean redistricting has entirely concluded until the next apportionment. As with every contemporary redistricting cycle, legal challenges to some maps have been made, which can necessitate further congressional district changes. 2020 Census and Apportionment Delays The onset of the COVID-19 pandemic led to certain delays in 2020 census data collection and delivery. Multiple bills were introduced in Congress that would have adjusted statutory deadlines for the Census Bureau to deliver apportionment data to the President or redistricting tabulations to states, but no statutory changes were enacted. On March 18, 2020, the Census Bureau temporarily suspended 2020 field operations. On April 13, 2020, the Bureau announced field offices would close through June 1. Under its final revised schedule, and following a U.S. Supreme Court ruling, the Bureau accepted census responses until October 15, 2020, two and a half months later than usual. The Bureau announced on January 28, 2021, that apportionment counts would be available by April 30, 2021; those were released April 26, 2021. A second announcement on February 12, 2021, indicated states would receive redistricting data by September 30, 2021. Redistricting data were released August 12, 2021, in the “legacy format” the Bureau has used since 2000, along with support materials for users; a subsequent release of a different data format became available September 16 at https://data.census.gov/. Apportionment and Seat Number Changes The 2020 census apportionment resulted in House seat losses for seven states and gains for six states, distributed as shown in Table 1. The U.S. apportionment population increased by 7.1% since 2010, to 331,108,434 individuals, and the average congressional district size increased to 761,169 individuals. Six states are to have a single House seat and did not need to draw district boundaries. Table 1. Loss or Gain of U.S. House Seats in States Following 2020 Census Lost House Seats Gained House Seats State Seat Change State Seat Change California -1 Colorado +1 Illinois -1 Florida +1 Michigan -1 Montana +1 New York -1 North Carolina +1 Ohio -1 Oregon +1 Pennsylvania -1 Texas +1 West Virginia -1 Source: U.S. Census Bureau, “Table D1. Number of Seats Gained and Lost in U.S. House of Representatives by State: 2020 Census,” 2020 Census Apportionment Results, April 26, 2021, at https://www2.census.gov/programs-surveys/decennial/2020/data/apportionment/apportionment-2020-tableD.xlsx. Method and Timing for Congressional Redistricting States vary in their redistricting processes, but congressional district boundaries are typically determined by a commission or state legislature, as shown in Figure 1. Of the 44 states with multiple House seats following this apportionment, 11 states gave redistricting commissions the authority to determine congressional districts, and 33 states gave this responsibility to their legislatures. Courts also could create district maps if a commission or legislature is unable to complete redistricting (depending on state law), or if legal challenges are made to a completed map. Figure 1. State Redistricting Methods / Source: CRS compilation, based on information from Ballotpedia and the National Conference of State Legislatures. Graphic created by Amber Hope Wilhelm, CRS Visual Information Specialist. Notes: Iowa has nonpartisan legislative staff create its redistricting maps but requires legislative approval to enact them. In New York, redistricting plans also require gubernatorial approval. The timelines for states’ redistricting processes also vary, and deadlines, if specified, may be an exact date or a date dependent upon another event (e.g., the end of the legislative session; or a certain length of time after redistricting data is delivered or a commission is formed). Most states completed congressional redistricting later relative to Census Day (April 1 of the year ending in “0”) after the 2020 census than they did after the 2010 census. Of the 44 states with multiple House districts following the 2020 census, 18 had statutory or constitutional deadlines related to congressional redistricting. Many of those states were able to meet their expected deadlines, and some states were able to adjust legislative session dates (Indiana, Iowa) or deadlines (Iowa, Oregon). States with no congressional redistricting deadline generally needed to complete initial congressional redistricting with enough time to prepare for applicable candidate filing deadlines or primary elections. Another option was postponing those dates. State legislatures changed candidate filing deadlines in five states (Kentucky, Nebraska, Ohio, Texas, and Virginia) and primary dates in two (Texas and Virginia). Courts made changes to filing deadlines in four states (Alabama, Maryland, North Carolina, and Pennsylvania) and to primary dates in three (Maryland, North Carolina, and New York). The two examples below provide some details about the first and last states to enact congressional district maps in the current redistricting cycle. These are intended as illustrations and are not necessarily representative of the redistricting process across other states. Oregon was the first to enact its initial congressional maps after the 2020 census on September 27, 2021. In comparison, after the 2010 census, Oregon enacted its maps on June 10, 2011. Oregon’s redistricting plan was enacted 162 days before its candidate filing deadline on March 8, 2022, and 232 days before its primary election on May 17, 2022. New Hampshire was the last state to enact its initial congressional district maps on May 31, 2022. In comparison, after the 2010 census, New Hampshire enacted its maps on April 23, 2012. New Hampshire’s redistricting plan was enacted 10 days before its candidate filing deadline on June 10, 2022, and 105 days before its primary election on September 13, 2022. Although all states with multiple House seats completed initial congressional district maps, legal challenges may result in further district changes. At the time of writing, legal challenges have been made to maps in 21 states, and court decisions affecting congressional maps have been made in 8 states.

What this is

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