Omaha is the most populous city in the U.S. state of Nebraska and the county seat of Douglas County. Omaha is in the Midwestern United States on the Missouri River, about 10 mi north of the mouth of the Platte River. The nation's 40th-most populous city, Omaha's 2020 census population was 486,051.Omaha is the anchor of the eight-county, bi-state Omaha–Council Bluffs metropolitan area. The Omaha metropolitan area is the 58th-largest in the United States, with a population of 967,604.