Lancaster County is a county located in the U.S. state of Nebraska. As of the 2020 United States Census, the population was 322,608, making it the second-most populous county in Nebraska. Its county seat is Lincoln, the state capital. The county was created in 1859.

Lincoln is the capital city of the U.S. state of Nebraska and the county seat of Lancaster County. The city covers 100.4 square miles (260.035 km2) with a population of 292,657 in 2021. It is the state's 2nd most populous city and the 73rd-largest in the United States. Lincoln is the economic and cultural anchor of a substantially larger metropolitan area in southeastern Nebraska, the Lincoln Metropolitan and Lincoln-Beatrice Combined Statistical Areas. The statistical area is home to 361,921 people, making it the 104th-largest combined statistical area in the United States.