Buffalo County is a county in the U.S. state of Nebraska. As of the 2010 census, the population was 46,102, making it Nebraska's fifth-most populous county. Its county seat is Kearney. The county was created in 1855 and later organized in 1870. It was named after the then-prevalent buffalo herds. Buffalo County is part of the Kearney, NE Micropolitan Statistical Area.