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Congressional Apportionment

Congressional Apportionment

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Within Congressional Apportionment

About This Topic
America Counts: Stories
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Data
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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 distributing the 435 memberships, or seats, in the U.S. House of Representatives among the 50 states.

Featured

About Congressional Apportionment
Methodology

Historical Perspective
Methodology

Computing Apportionment

Data

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Table

2020 Census Apportionment Results

April 26, 2021

Congressional seats were apportioned among the 50 states based on the 2020 Census population counts. Apportionment results from 1790 to 2020 are also shown.
Table

Historical Apportionment Data (1910-2020)

April 26, 2021

Historical apportionment data for the nation and states.
Table

2010 Census Apportionment Results

December 01, 2010

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

Videos

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Video

2020 Census: What is Apportionment? Tagalog / Tagalog

April 26, 2021
Video

2020 Census: What is Apportionment? Arabic / العربية

April 26, 2021
Video

2020 Census: What is Apportionment? Japanese / 日本語

April 26, 2021
Video

2020 Census: What is Apportionment? Korean / 한국어

April 26, 2021

America Counts

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Population

New Census Bureau District Profiles of 118th Congress

January 26, 2023

Welcoming the new congress with special social, economic, housing and demographic profiles of each congressional district.
Population

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

April 26, 2021

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

First 2020 Census Population Counts Will Be Released Today

April 26, 2021

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

Visualizations

Congressional Apportionment

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

April 26, 2021
Congressional Apportionment

Historical Apportionment Data Map (Interactive)

April 26, 2021

This interactive tool enables users to view more than 10 decades of apportionment and population data.
Congressional Apportionment

Changing Ranks of States by Congressional Representation

August 30, 2012
Congressional Apportionment

2010 Census: Apportionment of the U.S. House of Representatives Map

December 31, 2010

These maps show the change in the number of seats in the U.S. House of Representatives apportioned to each state between 2000 and 2010.

Publications

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Publication

Congressional Apportionment: 2020 Census Brief

May 2023

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

Strength in Numbers: A Guide to the 2020 Census Redistricting Data

September 16, 2021

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

Congressional Apportionment: 2010 Census Brief

November 01, 2011

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

Blogs

Director's Blog

The 2020 Census: Our Growing Nation

April 26, 2021

The U.S. Census Bureau released results from the 2020 Census, marking the 24th time the nation’s population has been counted.
Random Samplings Blog

Apportionment Population Counts and What to Expect on Release Day

April 26, 2021

Here at the U.S. Census Bureau, we’re excited to be nearing the important milestone of delivering the first results from the 2020 Census — the apportionment population counts.
Random Samplings Blog

How Apportionment is Calculated

April 26, 2021

In this blog, we will talk about how we calculate the apportionment of seats in the U.S. House of Representatives.

Press Kit

Press Kit

2020 Census Apportionment Counts Press Kit

February 22, 2021

The U.S. Census Bureau will release the congressional apportionment population counts and number of representatives for each of the 50 states.

All Subtopics Within 'Public Sector'

Building Permits

Data on the number of new housing units authorized by building permits. The data are from the Building Permits Survey.
Census of Governments

Identifies the scope and nature of the nation's state and local government sector including public finance and public employment and classifications.
Congressional Apportionment

Information about congressional apportionment for the current and past Decennial Censuses.
Congressional and Intergovernmental

This office advises Congress, and tribal and intergovernmental associations on Census Bureau programs and policies, and advises the Census Bureau’s management.
Government Employee Retirement Systems

Government Retirement Systems provides revenues, expenditures, financial assets, and membership information for state and local government retirement systems.
Government Employment & Payroll

Statistics on the number of state and local government civilian employees and their gross payrolls for the month of March.
Government Finances (Local Gov Finance/State Gov Finance)

Government finances include revenues, expenditures (spending), debt, and assets (cash and security holdings).
Government Organization & Structure

Information about state and local governments, including the number of governments in the U.S.
Government Taxes (State Tax Collections/ Quarterly Tax Revenues)

State and local government tax collections by major tax category including property, income and sales taxes.
Program Income and Public Assistance

Public assistance refers to assistance programs that provide either cash assistance or in-kind benefits to individuals and families from any governmental entity
Redistricting Data

The Census Bureau provides state legislatures with the small area census population tabulations necessary for legislative redistricting.
Survey of State Government Research and Development (SGRD)

Measures the extent of R&D activity performed and funded by the governments of each of the nation’s 50 states, the District of Columbia, and Puerto Rico.
Voting and Registration

In election years, the Current Population Survey collects data on reported voting and registration, and later reports stats by turnout, age, race and origin.

You May Be Interested In

Redistricting Data Program

Public Law 94-171 requires the Census to provide state legislatures with the small area census population tabulations necessary for legislative redistricting.

2020 Census Data Quality

We check the quality of our work every step of the way. When we release data, we make sure they meet our quality standards.

Visualization

Historical Apportionment Data Map (Interactive)

This interactive tool enables users to view more than 10 decades of apportionment and population data.

Page Last Revised - June 20, 2025

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