Congressional District
One of 435 geographic divisions of the United States, each represented by a member of the U.S. House of Representatives.
Congressional districts are redrawn after each decennial Census to reflect population changes, with each district containing roughly equal population (approximately 760,000 as of the 2020 Census). State legislatures or independent commissions draw district boundaries, and the resulting maps often split cities, counties, and ZIP codes.
ZIP code databases commonly include a congressional district field because businesses and political organizations need to identify which district(s) a ZIP code falls within. Since ZIP codes and congressional districts follow different boundary logic, a single ZIP may span two or more districts.
The current 118th Congress districts are based on 2020 Census redistricting. Six states (Alaska, Delaware, North Dakota, South Dakota, Vermont, Wyoming) have a single at-large district.