U.S. Highway 20 (US-20) is a part of the United States Numbered Highway System that runs for 3,365 miles (5,415 km) from Newport, Oregon, to Boston, Massachusetts. Within the state of Nebraska, it is a state highway that begins on the Wyoming–Nebraska state line west of Harrison near the Niobrara River and runs to the Nebraska–Iowa state line in South Sioux City. Throughout its 431.60-mile (694.59 km) length, the route passes through a diverse range of landscapes, including bluffs and escarpments in the Nebraska Panhandle, the Sandhills in the northern part of the state, and rolling hills and plains as the highway approaches the Missouri River valley south of Sioux City, Iowa. Throughout its length, US-20 is a two-lane highway with the exception of the easternmost 8.45 miles (13.60 km), which is a four-lane divided highway, the last 3.21 miles (5.17 km) of which is concurrent with Interstate 129 (I-129). The 197 miles (317 km) between the Wyoming border and Valentine is designated as the Bridges to Buttes Byway, one of nine scenic byways in the state of Nebraska.

South Sioux City is a city in Dakota County, Nebraska, United States. It is located immediately across the Missouri River from Sioux City, Iowa, and is part of the Sioux City, IA-NE-SD Metropolitan Statistical Area. As of the 2010 census, the city population was 13,353, making it the 14th most populous city in Nebraska.