Ofu and Olosega are parts of a volcanic doublet in the Manuʻa Islands, which is a part of American Samoa in the Samoan Islands. These twin islands, formed from shield volcanoes, have a combined length of 6 km and a combined area of 12 square kilometers. Together, they have a population of about 500 people. Geographically, the islands are volcanic remnants separated by the narrow, 137-meter-wide (449-foot)) Āsaga Strait, composed of shallow-water coral reef. Before 1970, people crossed between the two islands by waiting until low tide and then wading across the shallow water of the strait. Since 1970, there has been a bridge over the strait, providing a single-lane road that connects the two islands.

The Manuʻa Islands, or the Manuʻa tele, in the Samoan Islands, consists of three main islands: Taʻū, Ofu and Olosega. The latter two are separated only by the shallow, 137-meter-wide Āsaga Strait, and are now connected by a bridge over the strait. The islands are located some 110 kilometers east of Tutuila and are a part of American Samoa, an unincorporated territory of the United States. Their combined area is 56 square kilometers, and they have a total population of 1,400. Taʻu is the largest of these islands, with an area of 44 km2 (17 sq mi), and it has the highest point of the Manuʻa, at 931 meters. Politically, the islands form the Manuʻa District, one of the three administrative divisions of American Samoa.