Congressional Apportionment

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Congressional Apportionment

The Constitutional basis for conducting the decennial census is to reapportion the U.S. House of Representatives. Apportionment is the process of dividing the 435 memberships, or seats, in the U.S. House of Representatives among the 50 states.

Capitol building at night with street and car lights, Washington DC USA

Data

Table | April 26, 2021

Historical Apportionment Data (1910-2020)

Historical apportionment data for the nation and states.

Table | April 26, 2021

2020 Census Apportionment Results

Congressional seats were apportioned among the 50 states based on the 2010 Census population counts. Apportionment results from 1790 to 2010 are also shown.

Table | December 2010

2010 Census Apportionment Results

Congressional seats were apportioned among the 50 states based on the 2010 Census population counts. Apportionment results from 1790 to 2010 are also shown.

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Videos

¿Qué es la distribución proporcional de distritos congresionales?

2020 Census: What is Apportionment?

2020 Census: What is Apportionment? Japanese / 日本語

America Counts

First 2020 Census Data Release Shows U.S. Resident Population of 331,449,281

Some states will gain or lose seats in the U.S. House of Representatives based on 2020 Census population counts.

First 2020 Census Population Counts Will Be Released Today

The 2020 Census apportionment population counts will be used to determine each state’s congressional representation for the next decade.

Visualizations

2020 Census Map: Apportionment of the U.S. House of Representatives

2020 Census: Apportionment of the U.S. House of Representatives

Historical Apportionment Data Map (Interactive)

2020 Census: Operational Quality Metrics (Interactive)

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Publications

Publication | November 2011 | Kristin D. Burnett

Congressional Apportionment: 2010 Census Brief

Trends in congressional apportionment and the apportionment population—what it is, who is included, and what method is used to calculate it.

Publication | July 2010

Strength in Numbers: Your Guide to Census 2010 Redistricting Data

This brochure explains where census numbers come from and the role they have in the way states redraw the boundaries of their legislative districts.

Publication | July 2010

Censo del 2010 de Puerto Rico para la Redistribución de los Distritos

Este folleto explica de dónde provienen los números del censo y cómo son usados para determinar los límites de los distritos legislativos en Puerto Rico.

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Congressional Apportionment

Congressional Apportionment

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