county, north-central Pennsylvania, U.S., consisting of a mountainous region on the Allegheny Plateau. The principal stream is Sinnemahoning Creek, which divides itself into the Bennett and Driftwood branches. Parklands include Elk State Forest and Sinnemahoning, Bucktail, and Sizerville state parks.

Cameron county was created in 1860 and named for the 19th-century politician Simon Cameron (Cameron, Simon). County residents formed the Bucktail Regiment of the Pennsylvania Reserve Corps during the American Civil War. The county seat is Emporium. Lumbering became a major industry in the 19th century, but manufacturing is now the main economic activity. Cameron county is one of the least populous counties in Pennsylvania. Area 397 square miles (1,029 square km). Pop. (2000) 5,974; (2007 est.) 5,349.