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Apportionment Resources

What is Apportionment?

Apportionment is the process of dividing the 435 memberships, or seats, in the U.S. House of Representatives among the 50 states based on the apportionment population counts from the decennial census. Article I, Section 2 of the U.S. Constitution requires that a census of the population be taken every 10 years to apportion seats in Congress. 

Teach about apportionment using these activities and resources:

Apportionment 101 Fact Sheet

This fact sheet introduces students to apportionment by discussing what it is, and the impact it has on their state's place in the House of Representatives and the redrawing of legislative boundaries.

Interactive Historical Apportionment Data Map

This interactive map enables users to view more than 10 decades of apportionment data including population change and population density based on all people living in the United States at the time of each census. The warm-up activity challenges students to analyze the data contained in the map to learn more about their state's apportionment history.


Classroom Activities

These grade appropriate activities were designed specifically to teach students about congressional apportionment. They will learn what apportionment is, how it works, why it's important and how it relates to the decennial census. Each has a teaching guide to help instruct the activity.


Warm-Up Activities

These warm-up activities can be used at various grade levels and are designed to give students a basic understanding of apportionment. They are great class-starters and only take a short amount of time to complete.



View these animated videos to learn how apportion works and to see the formular used to ensure equal representation for all. 



These historical visualizations show the number of congressional representatives apportioned to each state as a result of U.S. population counts from the 2010 and 2000 Censuses. 



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