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.

In the US state of Iowa, Interstate 29 (I-29) is a north–south Interstate Highway which closely parallels the Missouri River. I-29 enters Iowa from Missouri near Hamburg and heads to the north-northwest through the Omaha–Council Bluffs and the Sioux City areas. It exits the state by crossing the Big Sioux River into South Dakota. For its entire distance through the state, it runs on the flat land between the Missouri River and the Loess Hills.