U.S. Decennial Census: Population and Housing Counts for Representation and Planning

Overview of the U.S. decennial census: how the Census Bureau collects population and housing counts and how those data shape congressional apportionment, redistricting, government funding, planning, and research.

Author: Leandro Alegsa Creation date: November 13, 2022 Last updated: April 10, 2026

United States Census refers to the nationwide population count that the federal government carries out every ten years. The U.S. Constitution requires this decennial enumeration, conducted in years ending in “0,” and it has been performed since 1790. The census is a form of census specific to the United States and provides the baseline data used for many civic and budgetary decisions.

What the count measures

The process consists of two principal components taken at the same time: a census of people (the population count) and a census of housing. The population count has been collected since 1790; the housing count, which records numbers of residential housing units, has been included since 1940. Together these datasets inform demographic statistics, trends, and official totals.

Primary uses

Apportionment: census results determine how many seats each state receives in the House of Representatives, and they are the starting point for state-level redistricting.
Funding and planning: federal and state agencies use census figures to guide the distribution of many types of government resources and to plan services and infrastructure.
Research and policy: population and housing data support academic research, business planning, and public policy development.

Administration and history

Responsibility for organizing and carrying out the census falls to the United States Census Bureau, a federal agency that manages questionnaire design, data collection, processing, and the release of aggregate statistics. The first post‑Revolution federal enumeration was taken in 1790; at that time the task was overseen by the Secretary of State, Thomas Jefferson, who helped arrange the initial count.

Over more than two centuries the census has evolved in methods and scope, but its core purpose—providing an accurate, periodic count of the population and housing for representation and public administration—remains unchanged.

Questions and Answers

Q: What is the United States Census?

A: The United States Census is a census done in the United States every ten years.

Q: Why is it done every ten years?

A: It is required by the United States Constitution which calls for a decennial census done in years ending in "0" since 1790.

Q: How many census counts are taken concurrently?

A: It is actually two census counts taken concurrently (at the same time).

Q: What is the first census count?

A: The first is the census of the population, taken from 1790 to the present.

Q: What is the second census count?

A: The second is the census of housing, which counts the number of residential housing units, and was taken from 1940 to the present.

Q: What are the uses of the census count?

A: Among other uses, the count is used to determine how many places in the House of Representatives each state has. It also determines how much government money is spent in different locations.

Q: Who is responsible for the United States Census?

A: The United States Census Bureau is responsible for the United States Census. The first census after the American Revolution was in 1790. Secretary of State Thomas Jefferson was responsible for this first census.