The Census: Counting Heads

Contributor: Suzanne Riordan. Lesson ID: 13317

It's why Mary and Joseph went to Bethlehem, how William the Conqueror made his Domesday Book, and what happens in the U.S. every 10 years: the census! But is it just counting heads, or something more?


Civics, United States

learning style
Auditory, Visual
personality style
Beaver, Golden Retriever
Grade Level
Middle School (6-8), High School (9-12)
Lesson Type
Dig Deeper

Lesson Plan - Get It!

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It's very important to count heads correctly, especially if you're a large family going on a trip overseas!

Watch these Home Alone - Forgetting Kevin scenes from the 1990 movie, posted by Lizzie Devlon:

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  • What happened?

Because Mitch Murphy came over, asked a bunch of questions, and rummaged through someone's bag; his head got counted instead of Kevin's, and Kevin was left home alone!

  • What does this have to do with the census?

Read on!

A census is a way of counting the number of people in a certain area, and they have been taken throughout history.


The word census comes from the Latin word censare, which means to assess or to register.

The Romans are well-known for their censuses, which they used to tax all the people in their vast empire and get soldiers for their army. These early censuses usually counted only adult men, not women and children. In the Bible, it says that Joseph and Mary went to Bethlehem before Jesus' birth to be counted in the Roman census.

Other ancient civilizations held censuses too, including the Babylonians, Chinese, Greeks, and Egyptians.

Another famous census occurred in 1066, when William the Conqueror took a survey of all "his" lands in England, including who lived where and how much they owned. This was the first census in England, and its information is gathered in what is now called the Domesday Book.

The following video tells more about the history of censuses and how the results are used. Grab some paper and a pencil or pen! As you watch the video, write down the answers to these questions:

  • How did Florence Nightingale use census data?
  • How did Mozambique officials use it?
  • What things can disrupt census-taking?
  • What did Siberian census takers need to bring with them and why?
  • How many countries planned to conduct a census in 2020?
  • What does the United States use census results for?

History of the Census and Census-Taking Around the World by Population Reference Bureau:

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For this lesson, we're going to focus on the census in the United States, but you'll have a chance to research another country's census in the Got It? section.

U.S. Census

The U.S. Census is decennial. That means it occurs once every ten years. This is written in the Constitution, so the government has to do it. (But do people have to answer the questions? More on that later!)


The first census in America was taken in 1790. Many things have changed in the years since then!

In 2020, for the first time in history, Americans could fill out their census forms online. In the early years, census workers went door-to-door to ask questions. Later, census forms were mailed to every household. Then, census workers went and knocked on everyone's door to make sure the forms were completed.

Watch Evolution of the Census: Margo Anderson, from U.S. Census Bureau, to learn how census-taking has changed over the years:

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Watch this video made by the U.S. Census Bureau to explain why the census is taken:

2020 Census: What is the Census?:

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So, some of the reasons the census is taken are:

  • to determine boundaries of Congressional districts and to determine representation (The number of representatives a state has in the House of Representatives is based on the population.)
  • to get information for decisions on how money should be spent on roads, school, health care, and emergency services (A state with more people would need more money from the federal government for those things than a state with fewer people.)


The results of the census show us how much the population of the U.S. has grown. It also shows how much the population of each U.S. state has grown.

The census gives statisticians (people who study statistics, the science of collecting and understanding data) a lot of numbers to play around with. And they do like to play around with them!

Check out the following video, which shows the growth of each state every year since 1790. It looks like a race: who's going to win? (You can click around in the video to see different years; you don't have to watch the whole thing from beginning to end.)

United States Population by State (1790 - 2019) from Data is Amazing:

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So much interesting data is collected by the census including:

  • the average age of Americans
  • the number of males and females
  • whether more people live in rural or urban areas
  • at what age people get married
  • the percentage of each race

Discover this information and more with 225 years of statistics: How America has changed since 1790, from U.S. Census Bureau:

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Now, move on to the Got It? page, where you'll take a quiz to see how much you remember and compare census questions from different years or countries!

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