The Dismal River is a winding 71.9-mile-long (115.7 km) river in the state of Nebraska. It is formed by the confluence of two forks, one of which has its origins in Grant County and the other in Hooker County. The forks meet near Nebraska Highway 97 between Mullen and Tryon. From here the Dismal River flows east-southeast into Thomas County, crossing U.S. Highway 83 south of Thedford. Passing just south of the Nebraska National Forest, it turns slightly to the northeast before its confluence with the Middle Loup River just East of Dunning in Blaine County.