The Dutch Harbor Naval Operating Base and Fort Mears were the two military installations built next to each other in Dutch Harbor, on Amaknak Island of the Aleutian Islands in Alaska, by the United States in response to the growing war threat with Imperial Japan during World War II.

Originally planned to start at the same time as the Battle of Midway, it occurred a day earlier due to one-day delay in the sailing of Nagumo's task force.

The base remained an important part of coastal defenses for the remainder of World War II.

[2] Shortly after the end of World War II, the U.S. military abandoned its Dutch Harbor outposts.

In the late 1980s, the U.S. government finally funded a cleanup of the derelict fort, and the area was turned over for commercial use.