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Keystone is a small unincorporated community on Whidbey Island in Island County, Washington, in the northwestern United States.^[1] It is near the Keystone ferry landing, a dock at Keystone Harbor for the Washington State Ferries' Coupeville to Port Townsend route. The route provides a maritime link for State Route 20 across Admiralty Inlet to the Olympic Peninsula. Since its establishment in the 1930s,^{[citation needed]} the ferry route to Port Townsend was known as the Keystone-Port Townsend Ferry; the name was changed in 2010 at the suggestion of the Central Whidbey Chamber of Commerce in order to avoid confusion from tourists and visitors to Whidbey Island.^[2]

Keystone is located about four miles south of Coupeville, next to Fort Casey State Park, Camp Casey, and is two miles from Ebey's Prairie National Historic Preserve. There is a residential area and farms in Keystone, including the historic Crockett Barn located next to the Crockett Blockhouse and Crockett Lake. Currently, the only business in Keystone is Callen's Restaurant,^[3] located directly across Highway 20 from the ferry landing and boat launch parking area.