Cedar is an unincorporated community in southeastern Mahaska County, Iowa, United States. It lies along Iowa Highway 23 southeast of the city of Oskaloosa, the county seat of Mahaska County. Its elevation is 814 feet (248 m), and it is located at 41°12′45″N 92°31′25″W / 41.21250°N 92.52361°W / 41.21250; -92.52361 (41.2125,-92.5235). Although Cedar is unincorporated, it has a post office with the ZIP code of 52543, which opened on 19 June 1874. Cedar also has a Methodist church, Christian Reformed church, and a grain elevator.