▶ Watch Video: 2020 census data signals shift of political power in Congress

The Census Bureau released its most detailed look so far detailing the results of the 2020 census on Thursday afternoon, kickstarting what is expected to be a highly contentious battle as states begin redrawing the boundaries of congressional districts.

The data includes a breakdown of demographic categories like race, Hispanic origin and age, down to a neighborhood block. The bureau also posted demographic data for every city with over 5,000 residents.

The results showed the number of White residents in the U.S. declined over the past decade, falling by 8.6%, while the number of racial minorities spiked considerably. The adult population also grew faster than the nation as a whole, with 258.3 million people over the age of 18, a 10.1% increase since 2010.

The population figures and the block-by-block breakdown are needed for commissions and state legislatures to begin their once-in-a-decade process of redistricting: redrawing the boundaries of everything from congressional and legislative districts to city wards. In April, the Census Bureau unveiled the number of congressional seats each state will receive based on the decennial population count.

Thursday’s release serves as the starting pistol for the process. The data itself was released in a complicated, non-user-friendly format, and redistricting groups expect that commissions and state legislatures will need weeks to sort out and convert the data before they start redrawing maps.

A more user-friendly version of this data is slated to come out September 30. One vendor described Thursday’s data release as the “IKEA furniture” version: officials will have all the pieces, but will have to put it together themselves.

The urgency to get started on redistricting stems from delays in census data collection and each state’s constitutional deadlines for redistricting and candidate filing. Some states such as California, Texas and Illinois have pushed or are looking at pushing their deadlines back. Democratic and Republican groups expect at least 25 to 35 states will be done with their maps by the end of this year.

Some states like Colorado and Virginia have started holding public redistricting hearings or have released preliminary maps in order to get ahead of the process and meet their deadlines. Thursday’s data will help them craft their official maps. 

With Democrats holding onto a slim majority in the House, redistricting will have huge ramifications for determining which party controls the lower chamber after the 2022 midterm elections.

Texas, North Carolina and Florida have Republican legislatures in control of redistricting, and each state will add at least one congressional seat. Both Democrats and Republicans believe these legislatures will try to “gerrymander,” or draw lines in their political favor, enough districts to flip control of the House. 

Kelly Ward Burton, executive director of the National Democratic Redistricting Committee, wrote on Thursday that the group believes Republicans can draw 11 to 16 more seats in their favor in Texas, North Carolina, Florida and Georgia alone.

Democrats are also in control of drawing seats or have final approval on maps in historically gerrymandered states like Illinois, Maryland and New York. 

Thursday’s data release also impacts congressional and legislative candidates, who have been in limbo regarding where they are actually running due to the delay in map drawing. In his campaign launch, Texas Republican candidate Wesley Hunt wrote that he will announce the district he’ll run in “as soon as Texas releases their newly redrawn Congressional district lines.”

As part of a larger battle over voting rights, congressional Democrats have been pushing for passage of the For The People Act, which would mandate every state establish an independent commission for drawing congressional district lines. The bill has stalled in the Senate.