Milligan, IndianaMilligan, also called South Waveland, is an unincorporated community in Greene Township, Parke County, in the U.S. state of Indiana.HistoryA post office was established at Milligan in 1882, and remained in operation until 1957. The community was named for Joseph Milligan, a storekeeper.GeographyMilligan is located on Indiana State Road 236, at with an elevation of 794 feet.