An easy way to determine the county for a particular United States city is by visiting the National Association of Counties website. NACo allows users to search for their county by zip code, city name or state.
The United States Census Bureau's website is another way to accurately find out the county where a specific city is located. Users can find their county by inputting their city or town name, zip code or state name. If a person prefers to learn their county name offline, they can simply call their local USPS branch or city hall to get the information.