Semaphore is a north-western seaside suburb of Adelaide of the LeFevre Peninsula, 14 km (8.4 mi) from the CBD, in the Australian state of South Australia, and is part of the City of Port Adelaide Enfield. It is adjacent to Semaphore South, Glanville, Exeter and Largs Bay. The postcode for Semaphore is 5019. It is bounded to the north by Union and Hargrave Streets, to the south by Hart Street, to the west by Gulf St Vincent and to the east by Woolnough Road and Swan Terrace.