The Tuscarawas River is a principal tributary of the Muskingum River, 129.9 miles (209 km) long, in northeastern Ohio in the United States. Via the Muskingum and Ohio Rivers, it is part of the watershed of the Mississippi River, draining an area of 2,590 square miles (6,708 km²) on glaciated and unglaciated portions of the Allegheny Plateau.
It rises southwest of Hartville in northern Stark County, and initially flows westwardly, through Uniontown into southern Summit County, where it passes through the Portage Lakes area south of Akron, and the city of Barberton. From Barberton the Tuscarawas flows generally southwardly through Stark and Tuscarawas Counties, through the communities of Clinton, Canal Fulton, Massillon, Navarre, Bolivar, Zoar, Dover, and New Philadelphia. South of New Philadelphia the river turns to the southwest and west, flowing past Tuscarawas, Gnadenhutten, Port Washington, and Newcomerstown into Coshocton County, where it joins the Walhonding River at the city of Coshocton to form the Muskingum River. From Barberton downstream, the Ohio and Erie Canal was constructed in parallel to the river in 1828-1830; usage began declining in the 1850s, and the canal was damaged beyond repair by flooding in 1913. Portions of the canal's towpath route are maintained as a hiking and bicycling trail.
According to the Geographic Names Information System, the Tuscarawas River has also been known historically by the names Little Muskingum River, Mashongam River, Tuscarawa River, and Tuskarawas Creek.
At an upstream gauge in Massillon, the annual mean flow of the river between 1938 and 2005 was 466 ft³/s (13 m³/s). The highest recorded flow during the period was 10,700 ft³/s (303 m³/s) on July 5, 1969. The lowest recorded flow was 45 ft³/s (1.3 m³/s) on September 20, 1999.