Douglas Island is a tidal island in the U.S. state of Alaska. It is part of the city and borough of Juneau, just west of downtown Juneau and east of Admiralty Island. It is separated from mainland Juneau by the Gastineau Channel, and contains the communities of Douglas and West Juneau.
Douglas Harbor in Douglas, Alaska. Mayflower Island, in the midground at right, houses a U.S. Coast Guard station. Mount Juneau is in the background.
Photo of Douglas Island by Frank La Roche ca. 1897
Resting place of several members of the Taku's Raven Clan.
Mining operations at Treadwell Gold Mine on Douglas Island, circa 1900
A tidal island is a raised area of land within a waterbody, which is connected to the larger mainland by a natural isthmus or man-made causeway that is exposed at low tide and submerged at high tide, causing the land to switch between being a promontory/peninsula and an island depending on tidal conditions.
St Michael's Mount, Cornwall, at high tide, c. 1900
Cramond Island, Scotland, at high tide: the causeway is submerged, but the anti-boat pylons are still visible
Mont Saint-Michel in Normandy
Rough Island opposite Rockcliffe, Dumfries & Galloway, Scotland