Noun
a river that rises in northeastern South Dakota and flows southward to join the Missouri River at Sioux City, Iowa
Source: WordNetAt Sioux City the Big Sioux River comes in from the north. Source: Internet
Here in Watertown, the city has built over 20 miles of bike trails that follow the Big Sioux River in town, and loop around Lake Kampeska for a great work out. Source: Internet