Olosega is an island located in the Manuʻa Islands of American Samoa within the Samoan Islands. It forms part of a volcanic doublet along with its twin island, Ofu. These islands were created from shield volcanoes and have a combined area of 12 square kilometers and a total length of 6 kilometers.
The two islands are separated by the Āsaga Strait, a narrow body of water measuring 137 meters wide that consists of shallow-water coral reef. While residents previously waded across the strait during low tide, a single-lane bridge has connected Olosega and Ofu since 1970. The combined population of the two islands is approximately 500 people.