city, seat (1808) of Tuscarawas county, east-central Ohio, U.S. It lies along the Tuscarawas River, adjacent to the city of Dover, about 25 miles (40 km) south of Canton. It was founded in 1804 by John Knisely, a tavern keeper from York, Pa. Named for Philadelphia, Pa., the community developed after the American Civil War, when the utilization of large local coal and clay deposits spurred industrial development.

Manufactures include construction equipment, containers and bags, machine tools, rubber and plastic products, and industrial fans. The Tuscarawas campus of Kent State University (1963) is in the city. One of Ohio's major flood-control and recreation projects, the Muskingum Watershed Conservancy District, is headquartered in New Philadelphia. The nearby Zoar Village (now a state memorial) was a commercial settlement (1817–98) founded by German Separatists. Ohio's first European-established village, Schoenbrunn Village (1772–77; now restored as a state memorial), lies a short distance southeast. Inc. village, 1833; city, 1895. Pop. (2000) 17,056; (2005 est.) 17,430.