The San Juan Islands are an archipelago in the northwest corner of the contiguous United States between the US mainland and Vancouver Island, British Columbia, Canada. The San Juan Islands are part of the U.S. state of Washington.
In the archipelago, four islands are accessible by passenger ferry operated by the Washington State Ferries system.The United States Geological Survey (USGS) defines the San Juan Islands as the archipelago north of the Strait of Juan de Fuca, west of Rosario Strait, east of Haro Strait, and south of Boundary Pass.
Today, the San Juan Islands are an important tourist destination, with sea kayaking and orca whale-watching (by boat or air tours) two of the primary attractions.Politically, the San Juan Islands comprise, by definition, San Juan County
At mean high tide, there are over 400 islands and rocks in the archipelago, 128 of which are named, and over 478 miles (769 km) of Shoreline
.The majority of the San Juan Islands are quite hilly with some flat areas and valleys, often quite fertile, in between. The tallest peak is Mount Constitution, on Orcas Island
, at almost exactly a half-mile (800 m) elevation. The coastlines are a mix of sandy and rocky beaches, shallow and deep harbors, placid and reef-studded bays. Gnarled, ochre-colored madrona trees (Arbutus) grace much of the shorelines while evergreen fir and pine forests cover large inland areas.