Redistricting is the process by which district maps for the U.S. House of Representatives, state legislatures, and local governing bodies are redrawn. These maps are used to determine the voting base for elected officials. The purpose of the redistricting process is to account for population change and to ensure that the governing body’s districts have roughly equal populations in compliance with the one person, one vote requirements of the U.S. Constitution.

All congressional, state legislative, and local district lines must comply with certain federal constitutional and statutory requirements, including provisions designed to ensure that districts represent an equal population and do not racially discriminate. State law governs the remaining requirements. While criteria vary from state to state, common criteria traditionally include the following.

Regardless of who is drawing the lines, all line drawers must comply with the districting rules created by the United States Constitution and federal law. Each state generally has their own rules when it comes to what a line drawer may or may not consider when drawing maps.

The UCLA Voting Rights Project has compiled a list of terms often used when discussing redistricting, defining them in the dictionary below. The dictionary is organized in alphabetical order.