Crosby County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 5,133. The county seat is Crosbyton. The county was founded in 1876 and later organized in 1886. Both the county and its seat are named for Stephen Crosby, a land commissioner in Texas. Crosby County, along with Lubbock and Lynn Counties, is part of the Lubbock Metropolitan Statistical Area.