Sioux Falls is the most populous city in the U.S. state of South Dakota and the 145th-most populous city in the United States. It is the county seat of Minnehaha County. and also extends into Lincoln County to the south. It is the 47th fastest-growing city in the United States and the fastest-growing metro area in South Dakota, with a population increase of 22% between 2000 and 2010.As of 2018, Sioux Falls had an estimated population of 183,200. The metropolitan population of 251,854 accounts for 29% of South Dakota's population. It is also the primary city of the Sioux Falls-Sioux City Designated Market Area, a larger media market region that covers parts of four states and has a population of 1,043,450. Chartered in 1856 on the banks of the Big Sioux River, the city is situated in the rolling hills at the junction of Interstate 90 and Interstate 29.