Omaha ( OH-mə-hah) is the largest 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 miles (15 km) north of the mouth of the Platte River (also known as the Nebraska River). The nation's 40th-largest city, Omaha's 2019 estimated population was 478,192, compared to its 2010 census population of 408,958. It is the second-largest city in the Great Plains states (behind Oklahoma City), the second-largest city along the Missouri River (behind Kansas City, Missouri), and the seventh-largest city in the Midwest.
Omaha is the anchor of the eight-county, bi-state Omaha-Council Bluffs metropolitan area. The Omaha Metropolitan Area is the 59th largest in the United States, with an estimated population of 944,316 (2018). The Omaha-Council Bluffs-Fremont, NE-IA Combined Statistical Area (CSA) encompasses the Omaha-Council Bluffs MSA as well as the separate Fremont, NE Micropolitan Statistical Area, which consists of the entirety of Dodge County, Nebraska. The total population of the CSA was 970,023 based on 2017 estimates. Approximately 1.3 million people reside within the Greater Omaha area, within a 50 mi (80 km) radius of Downtown Omaha.
Omaha's pioneer period began in 1854, when the city was founded by speculators from neighboring Council Bluffs, Iowa.