Douglas County is a county in the U.S. state of Nebraska.
As of the 2010 United States Census, the population was 517,110. It is the state's most populous county, home to over one-fourth of Nebraska's residents. Its county seat is Omaha, the state's largest city. The county was established in 1854 and named after Stephen A. Douglas (1813–1861), Senator from Illinois.
Douglas County is on the east side of Nebraska. Its east boundary line abuts the west boundary line of the state of Iowa, across the Missouri River. The Elkhorn River runs southward through the west-central part of Douglas County, and it is bordered on