Redistricting Glossary


The process of assigning electoral seats to various political groupings such as states, counties, and districts.


The Census counts every person living in the United States and its five territories. It happens every 10 years and the results are used to determine the number of seats each state will have in the US House of Representatives. It is also used to draw congressional and state legislative districts.

Census Block

The smallest unit of geography of the Census.

Census Block Group

A collection of contiguous census blocks used by mapmakers to draw districts. Composed of 600 - 3,000 people.


When voting district lines across the country are redrawn to determine who represents the people of your state.

Redistricting Commission

A government body that researches, drafts, and/or draws district maps for legislatures and Congress.

Redistricting Criteria

The guidelines that state legislatures and other map drawers must follow in order to create a district.

Communities of Interest

A geographic area that shares cultural, historical, or economic interests. Mapping communities of interest encourages the drawing of fairer voting districts.


The boundaries that define a group of people that vote for an elected official together.

Contiguous District

When there are no gaps in a district and it has connecting boundaries.


A file that is compatible with most map drawing softwares.


A plan or map that is intentionally drawn to advantage or disadvantage a specific group.


The act of splitting apart members of one group into multiple districts to the point that they are a super-minority in that district. This reduces the electoral strength of the group overall.


The act of grouping together members of one group within a district to the point that they are a super-majority in that district. This reduces the electoral influence of the group overall.

More Information
“What is the 2020 Census?”, US Department of Commerce,