Where is Mason County?

6 Mason Counties in 6 states · 158,249 people (2025)

There are 6 counties named Mason County in the United States, in Illinois, Kentucky, Michigan, Texas, Washington and West Virginia. The most populous is Mason County, Washington (county seat: Shelton), with 71,165 people in 2025. 3 of them are named after George Mason, American delegate from Virginia to the U.S. Constitutional Convention (1725-1792).

Map of the United States showing where all 6 Mason Counties are, labeled by state
Every Mason County in the United States (red), labeled with its state. Boundaries: U.S. Census Bureau, 2025. Free to use with attribution (CC BY 4.0).

All 6 Mason Counties

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

StateCounty seatPopulation 2025Land area (sq mi)EstablishedNamed after
Mason County, IllinoisHavana12,4115391841George Mason
Mason County, KentuckyMaysville16,9362401788George Mason
Mason County, MichiganLudington29,0404951840Stevens T. Mason
Mason County, TexasMason3,9909291858Fort Mason
Mason County, WashingtonShelton71,1659601854Charles H. Mason
Mason County, West VirginiaPoint Pleasant24,7074311804George Mason

Questions about Mason Counties

How many Mason Counties are there?

There are 6 Mason Counties in the United States, in Illinois, Kentucky, Michigan, Texas, Washington and West Virginia.

Which Mason County is the largest?

By population, Mason County, Washington (71,165 people in 2025). By land area, Mason County, Washington (960 sq mi).

Which Mason County is the oldest?

Mason County, Kentucky, established in 1788. The newest is Mason County, Texas (1858).

Why are there so many Mason Counties?

3 of the 6 are named after George Mason, American delegate from Virginia to the U.S. Constitutional Convention (1725-1792). Many counties took their names from the same founders, presidents and generals as new states were organized.

How do I find out which Mason 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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Other common county names