county, northeastern Pennsylvania, U.S., consisting of a mountainous region of the Allegheny Plateau bounded by New York state to the north. In addition to Stillwater and Quaker lakes, the principal waterways are the Susquehanna (Susquehanna River) and Lackawanna (west and east branches) rivers and Meshoppen, Tunkhannock, Snake, and Starrucca creeks. Salt Springs State Park is located north of Montrose, the county seat.

Hallstead and Great Bend were founded in 1787 along the Susquehanna River near the site of Tuscarora, an old Indian settlement. The county was created in 1810; its name probably was derived from two Delaware Indian words: sisku (“mud”) and hanne (“river”). The main economic activities are agriculture (milk and hay) and manufacturing (search and navigation equipment). Susquehanna county is one of seven completely rural counties in Pennsylvania. Area 823 square miles (2,132 square km). Pop. (2000) 42,238; (2007 est.) 41,123.