Swan Island is located on the Willamette River about 4.5 miles (7.2 km) downriver from downtown Portland, Oregon, United States. Although presently connected to the Willamette's east bank by land fill, it existed as a river island under natural conditions.

The Swan Island Municipal Airport was a joint civil-military airport that was operational on Swan Island in Portland, Oregon. Though it officially opened in 1927, the United States Postal Service had been using the airfield for a year. After the Portland–Columbia Super Airport was completed in the late 1930s, Swan Island Municipal Airport had little use since its runways were too small for newer aircraft and the low altitude made takeoffs and landings difficult. The airport was operational for nearly two decades, but due in part to the advances in aviation, it became obsolete soon after its construction. During World War II, a Kaiser shipyard was located at Swan Island. The shipbuilding facilities were acquired by the Port of Portland after the war.