Lancaster County, Nebraska

Lancaster County is a county located in the U.S. state of Nebraska. As of the 2020 census, the population was 322,608, and was estimated to be 334,049 in 2025, making it the second-most populous county in Nebraska. The county seat and the largest city is Lincoln, the second-most populous city in Nebraska and the state capital. It is the 72nd-most populous city in the United States.

Lancaster County is part of the Lincoln, Nebraska metropolitan area.

In the Nebraska license plate system, Lancaster County was represented by the prefix "2" (as it had the second-largest number of vehicles registered in the state when the license plate system was established in 1922). In 2002, the state discontinued the 1922 system in the three most populous counties: Douglas, Lancaster, and Sarpy Counties.