Foster Township is located in Marion County, Illinois. The population was 405 at the 2000 census. Foster Township is a farming community that no longer has towns or villages within its boundaries. It is mainly a farming community with corn, wheat and soy beans being the major crop. Wildlife includes deer, turkey, rabbits and raccoons and an occasional wolf or bear. The township consists of flat prairie on the north and west and timber and hills in the south and east. It is located in the northern part of the county of Marion, bordering Fayette County on its north, and the townships of Kinmundy to its east, Tonti on its south, and Patoka to its west.