Omaha is the largest city in the state of Nebraska, United States, and is the county seat of Douglas County.GR: 6 It is located in the Midwestern United States on the Missouri River, about 20 miles (30 km) north of the mouth of the Platte River. Omaha is the anchor of the Omaha-Council Bluffs metropolitan area, with Council Bluffs, Iowa sitting adjacent to Omaha across the Missouri River. According to the 2008 estimate by the United States Census Bureau, Omaha's population was 432,921. The city is the nation's 42nd-largest, according to 2007 U.S. Census Bureau estimates; along with its suburbs Omaha formed the 60th-largest metropolitan area in the United States in 2000, with an estimated population of 837,925 residing in eight counties. There are more than 1.2 million residents within a 50 mile (80 km) radius of the city's center, forming the Greater Omaha area.

Omaha's pioneer period began in 1854 when the city was founded by speculators from neighboring Council Bluffs, Iowa. The city was founded along the Missouri River, and a crossing called Lone Tree Ferry earned the city its nickname, the "Gateway to the West." During the 19th century, Omaha's central location in the United States caused the city to become an important national transportation hub. Throughout the rest of the 19th century, the transportation and jobbing sectors were important in the city, along with its railroads and breweries.

In the 20th century, the Omaha Stockyards, once the world's largest, and its meatpacking plants, gained international prominence. Today, the city is the home to five Fortune 500 companies: ConAgra Foods, Union Pacific Corporation, Peter Kiewit and Sons, Inc., Mutual of Omaha Companies, and Berkshire Hathaway, the company headed by legendary investor and so-called Oracle of Omaha, Warren Buffett, the richest person in the world according to Forbes Magazine in 2008.Omaha is also the home to four Fortune 1000 businesses, TD Ameritrade, Valmont Industries, teleservices firm West Corporation and trucking concern Werner Enterprises. The First National Bank of Omaha is the largest privately held bank in the United States. Headquarters for the Leo A. Daly Co., HDR, Inc. and DLR Group, three of the world's top 30 architectural and engineering firms, are located in Omaha. The modern economy of Omaha is diverse and built on skilled knowledge jobs. In 2001, Newsweek identified Omaha as one of the Top 10 high-tech havens in the nation. Tourism in Omaha benefits the city's economy greatly, with the annual College World Series providing important revenue and the city's Henry Doorly Zoo serving as the top attraction in Nebraska.

A historic preservation movement in Omaha has led to a number of historic structures and districts being designated Omaha Landmarks or listed on the National Register of Historic Places. Since its founding, ethnic groups in the city have clustered in enclaves in north, south and Downtown Omaha. The city's history has included a variety of crime such as illicit gambling, riots, lynchings, and recently, gang violence. Today, the diverse culture of Omaha includes a variety of performance venues, museums, and musical heritage, including the historically-significant jazz scene in North Omaha and the modern and influential "Omaha Sound." Sports have been important in Omaha for more than a century, and the city currently hosts three professional sports teams. Omaha also has a number of recreational trails and parks located throughout the city.