New Philadelphia is a city in Tuscarawas County, Ohio, 96 miles (154 km) south of Cleveland on the Tuscarawas River. It was first incorporated in 1808. Coal and clay are found in the vicinity. In the past, mining interests and the manufacturing of steel, canned goods, roofing tile, sewer pipe, bricks, vacuum cleaners, stovepipes, carriages, flour, brooms, and pressed, stamped, and enameled goods occupied the people. In 1900, 6,213 people lived here; in 1910 8,542; in 1920, 10, 718; and in 1940, 12,328 people lived here. The population was 17,056 at the 2000 census. It is the county seat of Tuscarawas County.

As of the census of 2000, there were 17,056 people, 7,338 households, and 4,659 families residing in the city. The population density was 844.3/km² (2,188.0/mi²). There were 7,796 housing units at an average density of 385.9/km² (1,000.1/mi²). The racial makeup of the city was 96.89% White, 0.97% African American, 0.18% Native American, 0.49% Asian, 0.06% Pacific Islander, 0.49% from other races, and 0.93% from two or more races. According to the Census Bureau, Hispanic or Latino of any race were 1.33% of the population. Since the mid 90's, Tuscarawas County, Ohio, together with Holmes, Stark and Wayne Counties experienced a significant Hispanic immigration, led by recruitment at area chicken processing plants. One plant, Case Farms in Winesburg, maintained an employment of 525.