Lopez Island is the third largest of the San Juan Islands and an unincorporated town in San Juan County, Washington, United States. Lopez Island is 29.81 square miles (77.2 km2) in land area. The 2020 census population was 3,156, though the population swells in the summer, as second homes, rental houses, and campsites fill up.

The San Juan Islands is an archipelago in the Pacific Northwest of the United States between the U.S. state of Washington and Vancouver Island, British Columbia, Canada. The San Juan Islands are part of Washington state, and form the core of San Juan County.