San Juan County Washington (Historic Districts) has 8 places on the National Register of Historic Places including 3 places of National significance. Significant places include American and English Camps, San Juan Island, Roche Harbor and San Juan Island National Historic Site, Camp Nor'Wester and Krumdiack Homestead.
Prehistoric cultural affiliation(s) include Samish and Kwakiuti dating back to 2999 BC.
Some of the country's most noteable architects helped create the San Juan County places including Theodore & Thomas Tharald, Paul Kirk and Friedrich Krumdiak. Prominent architectural styles found in San Juan Country are .