St Martin-by-Looe (Cornish: Penndrumm) is a coastal civil parish in south Cornwall, England, United Kingdom. The parish is immediately east of the town and parish of Looe, seven miles (11 km) south of Liskeard. The parish is in the Liskeard Registration District and the population in the 2001 census was 321, which had increased to 429 at the 2011 census. To the north, the parish is bordered by Morval parish, to the east by Deviock parish, to the west by Looe parish and to the south by the English Channel. Until 1845 the parish also included East Looe.