Douglas County, incorporated in 1855, forms part of one of the nation's major metropolitan areas along the Missouri River, with Omaha as its largest city. The county has a broad-based economy with strong trade, service, and manufacturing sectors, with many corporations headquartered in the county. This is the major insurance and telemarketing center of the United States. The employment base is diverse and employment remains stable. Douglas County's unemployment rate has consistently remained below the state and national averages.