Washington Island Superlatives

Washington state has an unusually fine collection of islands: hundreds of sea islands in Puget Sound, the big islands of the Columbia River, and interesting lake islands, including the most populous lake island in the United States.




Largest island

The largest island in Washington is Whidbey Island, with an area of 172 sq mi / 445 sq km.  It is the 35th largest island of the United States.


Lake island

Washington’s largest lake island is Mercer Island, in Lake Washington, in greater Seattle, at 6.4 sq mi / 17 sq km.


River island

Washington’s largest river island is Puget Island, a 7.5 sq mi / 19.4 sq km island in the Columbia River.


Island on an island

The largest island on another island in Washington is a small island in Lake Campbell on southern Fidalgo Island.





Most isolated island

Smith Island, west of Whidbey Island, is about 5.4 miles / 8.5 km from the nearest larger island.


Lowest island

Washington has no islands below sea level.





About 160,000 people live on islands in the state, giving Washington one of the larger island populations in the United States.  Some 30,000 live on onbridged islands, more than in any other of the lower 48 states.


Most populous island

The most populous island in Washington is Whidbey Island, which had 58,211 inhabitants as of the 2000 census.


Most populous unbridged island

Washington has more inhabited, unbridged islands than most states.  The most populous island is Vashon, which in 2000 was home to 10,123 people.


Most populous lake island

Washington's most populous lake island is Mercer Island, in Lake Washington, in greater Seattle.  It was home to around 21,710 people as of 2005.


Most populous river island

Puget Island in the Columbia River had a population of 798 at the 2000 census.





Tallest island

Washington’s tallest island is Orcas Island, which rises 2,407 feet / 734 meters from sea level to the top of Mount Constitution.


Tallest lake island

Lake Washington’s Mercer Island is Washington’s tallest lake island: it rises about 370 feet / 113 meters above lake level.


Most common name

The most common names for islands in Washington are "goose island" and “sand island,” with 5 of each.


Most islands in one lake

Washington’s Potholes Reservoir has some 956 islands.


(Picture credits: Fidalgo vista courtesy Skycaptaintwo, Mercer Island bridge courtesy Mamamusings)



 SEE ALSO Island Misinformation and American Island Superlatives.



© Joshua Calder

Contact Joshua Calder at calder.josh[at]gmail.com with questions or suggestions. 

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