It lies between the mainland near the city of Steilacoom and Anderson Island near the extreme south end of Puget Sound.

The British explorer and navigator George Vancouver camped on Ketron Island in May of 1792.

The island was named for William Kittson, an employee of the Hudson's Bay Company, who supervised the construction of Fort Nisqually in 1833 and served as its chief factor.

[4] The entire island was bought by an entrepreneur in 1946 with plans to build 200 homes, but this attempt was abandoned due to the cost of a sewer system.

[5] On August 10, 2018, an empty Horizon Air Q400 was stolen from Seattle–Tacoma International Airport and crashed on the southern tip of Ketron Island, killing the sole occupant, Richard Russell.