Oak Lawn is a village in Cook County, Illinois, United States, adjacent to Chicago. It is the 22nd-most populous municipality in Illinois, with a population of 58,362 as of the 2020 census. Oak Lawn was first settled in 1835 and later incorporated in 1909. The village serves as a major medical and economic anchor for the southwest suburbs, notably hosting Advocate Christ Medical Center, one of the largest hospitals and Level I trauma centers in the state of Illinois.