New Philadelphia is a city in and the county seat of Tuscarawas County, Ohio, United States. The county's largest city, New Philadelphia is located on the Tuscarawas River. It is located 71 miles south of Cleveland and 119 miles northeast of Columbus. The population was 17,288 at the 2010 census.Because of the presence of coal and clay, early industry in the city centered on mining interests and the manufacture of steel, canned goods, roofing tile, sewer pipe, bricks, vacuum cleaners, stovepipes, carriages, flour, brooms, and pressed, stamped, and enameled goods.New Philadelphia is a principal city in the New Philadelphia–Dover, OH Micropolitan Statistical Area, which includes all of Tuscarawas County, as well as the southern regions of Northeast Ohio.