San Juan Islands National Monument spans the San Juan archipelago in Washington’s Salish Sea as about 75 separate federal sites totaling roughly 1,000 acres rather than a single continuous park. Created on March 25, 2013, when President Barack Obama used the Antiquities Act to designate existing federal land, it is managed by the Bureau of Land Management within the National Landscape Conservation System. The monument protects archaeological sites linked to Coast Salish peoples, lighthouses and relics from early European American settlement, and island habitats whose biodiversity and long human use together make the San Juans historically and environmentally significant.