Blakely Island in San Juan County, Washington is the sixth largest island in the San Juan Islands of Washington State, USA, encompassing a land area of 16.852 km² (6.507 sq m). It is separated from Cypress Island to the east by Rosario Strait. The population was 56 persons as of the 2000 census. There is no ferry service to Blakely Island. Access is only by boat or private ferry, arriving at the marina at the northern tip of the island. There is also a private airstrip for the exclusive use of property owners. The only services available on Blakely Island are at a general store, located at the marina. Blakely Island has no public access other than the marina on the north end. Blakely Island was named by Charles Wilkes during the Wilkes Expedition of 1838-1842, in honor of Johnston Blakeley, a naval commander during the War of 1812.