Answer:
Congressional district.
Step-by-step explanation:
In the United States, Congressional district is an electoral division that exist in order to elect the members of Congress. United States House of Representatives which is the lower chamber of the Congress has 435 seats. Size of each congressional district is determined based on the nationwide census and currently is set at approximately 711,000 people.
The most populous states have larger number of districts and thus can elect higher number of members of congress. California is currently being the largest with 53 districts, while such states as Alaska, Montana and Wyoming each have only one district.