Where Is Somerset County? All 4 Somerset Counties on a Map

Where is Somerset County?

4 Somerset Counties in 4 states · 505,083 people (2025)

There are 4 counties named Somerset County in the United States, in Maine, Maryland, New Jersey and Pennsylvania. The most populous is Somerset County, New Jersey (county seat: Somerville), with 356,486 people in 2025. 3 of them are named after Somerset, ceremonial county of England (use Q21694741 for administrative non-metropolitan county).

All 4 Somerset Counties

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

State	County seat	Population 2025	Land area (sq mi)	Established	Named after
Somerset County, Maine	Skowhegan	51,620	3,924	1809	Somerset
Somerset County, Maryland	Princess Anne	24,973	320	1666	Mary, Lady Somerset
Somerset County, New Jersey	Somerville	356,486	302	1688	Somerset
Somerset County, Pennsylvania	Somerset	72,004	1,075	1795	Somerset

Questions about Somerset Counties

How many Somerset Counties are there?

There are 4 Somerset Counties in the United States, in Maine, Maryland, New Jersey and Pennsylvania.

Which Somerset County is the largest?

By population, Somerset County, New Jersey (356,486 people in 2025). By land area, Somerset County, Maine (3,924 sq mi).

Which Somerset County is the oldest?

Somerset County, Maryland, established in 1666. The newest is Somerset County, Maine (1809).

Why are there so many Somerset Counties?

3 of the 4 are named after Somerset, ceremonial county of England (use Q21694741 for administrative non-metropolitan county). Many counties took their names from the same founders, presidents and generals as new states were organized.

How do I find out which Somerset 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.

What county am I in? →