
Sioux City was laid out in the winter of 1854–1855. 1859 map of route from Sioux City, Iowa, through Nebraska, to gold fields of Wyoming, partially following old Mormon trails. Sergeant Charles Floyd, a member of the Lewis and Clark Expedition, died here on August 20, 1804, the only death during the two and a half-year expedition. The first documented US citizens to record their travels through this area were Meriwether Lewis and William Clark during the summer of 1804. The area of Sioux City was inhabited by Yankton Sioux when it was first reached by Spanish and French furtrappers in the 18th century. Iowa is in the tallgrass prairie of the North American Great Plains, historically inhabited by speakers of Siouan languages. Main article: History of Sioux City, Iowa Sioux City and the surrounding areas of northwestern Iowa, northeastern Nebraska and southeastern South Dakota are sometimes referred to as Siouxland, especially by local media and residents. Sioux City is at the navigational head, or the furthest upstream point to which general cargo ships can travel, of the Missouri River, approximately 95 mi (153 km) north of the Omaha–Council Bluffs metropolitan area.

The Sioux City– Vermillion, IA–NE–SD Combined Statistical Area had a population of 175,638 as of 2020. Sioux City is the primary city of the five-county Sioux City, IA– NE– SD Metropolitan Statistical Area (MSA), with a population of 149,940 in the 2020 census. The city is also home to Chris Larsen Park, commonly referred to as "the Riverfront", which includes the Anderson Dance Pavilion, Sergeant Floyd Riverboat Museum and Lewis and Clark Interpretive Center.

The city is home to several cultural points of interest including the Sioux City Public Museum, Sioux City Art Center and Sergeant Floyd Monument, which is a National Historic Landmark. Sioux City is located at the navigational head of the Missouri River. The bulk of the city is in Woodbury County, of which it is the county seat, though a small portion is in Plymouth County. The population was 85,797 in the 2020 census, making it the fourth-largest city in Iowa. Sioux City ( / s uː/) is a city in Woodbury and Plymouth counties in the northwestern part of the U.S.
