Where is Knox County?

9 Knox Counties in 9 states · 744,778 people (2025)

There are 9 counties named Knox County in the United States, in Illinois, Indiana, Kentucky, Maine, Missouri, Nebraska, Ohio, Tennessee and Texas. The most populous is Knox County, Tennessee (county seat: Knoxville), with 511,453 people in 2025. 9 of them are named after Henry Knox, American general and Secretary of War (1750–1806).

All 9 Knox Counties

Sorted by state. Each link opens the county's map.

State	County seat	Population 2025	Land area (sq mi)	Established	Named after
Knox County, Illinois	Galesburg	47,767	716	1825	Henry Knox
Knox County, Indiana	Vincennes	35,652	516	1790	Henry Knox
Knox County, Kentucky	Barbourville	29,532	386	1799	Henry Knox
Knox County, Maine	Rockland	41,117	365	1860	Henry Knox
Knox County, Missouri	Edina	3,728	504	1843	Henry Knox
Knox County, Nebraska	Center	8,335	1,108	1857	Henry Knox
Knox County, Ohio	Mount Vernon	64,002	526	1808	Henry Knox
Knox County, Tennessee	Knoxville	511,453	508	1792	Henry Knox
Knox County, Texas	Benjamin	3,192	851	1858	Henry Knox

Questions about Knox Counties

How many Knox Counties are there?

There are 9 Knox Counties in the United States, in Illinois, Indiana, Kentucky, Maine, Missouri, Nebraska, Ohio, Tennessee and Texas.

Which Knox County is the largest?

By population, Knox County, Tennessee (511,453 people in 2025). By land area, Knox County, Nebraska (1,108 sq mi).

Which Knox County is the oldest?

Knox County, Indiana, established in 1790. The newest is Knox County, Maine (1860).

Why are there so many Knox Counties?

9 of the 9 are named after Henry Knox, American general and Secretary of War (1750–1806). Many counties took their names from the same founders, presidents and generals as new states were organized.

How do I find out which Knox County an address is in?

Open the county map of the state: it has a search box for cities, towns and ZIP codes. On a phone, the "what county am I in" tool on our sister site uses your location.

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