Seward County is a county in the U.S. state of Nebraska, United States. As of the 2020 United States Census, the population was 17,609. Its county seat is Seward. The county was formed in 1855, and was organized in 1867. It was originally called Greene County, and in 1862 it was renamed for William H. Seward, Secretary of State under Abraham Lincoln and Andrew Johnson. Seward County is part of the Lincoln, NE Metropolitan Statistical Area.