What Is a Census?

What Is a Census?

A census counts the population of a nation, state, or other geographic region. It records information about the population’s characteristics, such as age, sex, and occupation.


9 - 12+


Geography, Human Geography, Mathematics, Social Studies, World History

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A census counts how many people live in a nation, state, city, or other geographic area. It also records information about the population. For example, it records each person's age, sex, and job. National governments usually take censuses every five to 10 years.

Censuses give governments all kinds of useful information. For example, they show which cities are growing the fastest. They show how many children live in a particular area. If an area has more people, it needs more services. This information helps governments make decisions like where to build new roads or schools.

In some countries, censuses are used to figure out the right number of people in government. Each state in the United States is made up of many counties. In each county, citizens vote for their representatives. A representative is a politician who acts and speaks for a community. Citizens vote for the representative they like best. Counties with larger populations are allowed to have more representatives in the state's government.

The same is true for the federal, or national, government. States with a large population have more lawmakers in the House of Representatives. The House is part of the U.S. Congress.

Historical Censuses

Censuses have been taken for thousands of years. In ancient Rome, men had to go to the census-takers from time to time. A census-taker is someone who gathers information for the census. Each man had to list his family members. He also had to say how much property he owned. The Roman government ranked citizens by their property. Men with valuable property were given more rights and freedoms.

The Incan Empire in South America had its own kind of census. In the 1400s, the Incas did not have a written language. Instead, they recorded information on quipus. A quipu is a rope made from animal hair or cotton cords. In order to record numbers or other information, the Incas made knots on the quipus. The Incan government used these cords to make a census of the population. Quipus recorded the ages, jobs, and property of Incan citizens. Today, a few villages in the country of Peru still use the quipu system.

National Censuses

Censuses are a set of questions. Citizens answer these questions by filling out a form or by speaking with a census-taker.

New ways of taking censuses have helped governments get better results. For example, in 2006, Australia allowed citizens to answer census questions online. More people participated than ever before.

Nations run their censuses differently. Brazil has one of the most detailed censuses in the world. It includes information about every region, state, city, town, and neighborhood.

Brazil has been trying to make sure its censuses cover as much of the population as possible. In 2010, it started using new, handheld census computers. Census-takers now carry these with them. The computers can translate questions into different native languages. Native people are those who lived in the country before white colonists came from Europe hundreds of years ago.

Censuses take a long time and cost money. It takes many census-takers to carry out a census, and they all have to get paid. It's worth it, though. Census-takers bring together valuable information about a country's people and communities. Leaders and citizens need this information to improve the places they live.

Fast Fact

Counting Up China
How does the most populated country in the world count its population? China, with a population of about 1.4 billion, needed 6 million census-takers in 2010 to count every man, woman, and child in the country!

Fast Fact

Using the Force
More than 400,000 people wrote "Jedi" as their religion on the 2001 census forms in Australia, Canada, England, New Zealand, Scotland, and Wales. More people considered themselves Jedi, an order of people from the Star Wars movies, than Jewish.

Fast Fact

Census of Marine Life
In 2010, scientists finished the first-ever census of life in the world's oceans. The 10-year project, partly financed by the National Geographic Society, found there are nearly 250,000 known species in the sea. It also found more than 6,000 potentially new species.

Fast Fact

Going Dutch
The Netherlands has not conducted an official census since 1971 out of concern for individual privacy.

Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Diane Boudreau
Melissa McDaniel
Erin Sprout
Andrew Turgeon
Mary Crooks, National Geographic Society
Tim Gunther, Illustrator
Jeannie Evers, Emdash Editing, Emdash Editing
Kara West
Educator Reviewer
Nancy Wynne
National Geographic Society
Last Updated

October 19, 2023

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