'Ofu' and 'Olosega' are parts of a volcanic doublet in the
Manu‘a Group of the Samoa Archipelago—part of
American Samoa. Although geographically separate volcanic remnants, only a narrow straight (Asaga) naturally bridged by a shallow
coral reef separates them. Before 1970, one had to wade between the two islands at low tide; now a road bridge over the straight connects villages on Ofu with those on Olosega.
Ofu
Ofu is the western part of the volcanic outcrop of Ofu-Olosega Island. The main village of
Ofu is located on the western shore, protected behind an offshore islet (eroded
tuff cone) known as
Nu‘utele. Ofu has a small airport and a boat harbor that serve the population on Ofu and Olosega.

South shore of Ofu seen from Olosega across the narrow straight that separates them. The sharp peak, an eroding dike complex, is named Sunu‘itao.
Most of the southern shore and associated coral reef are part of the
National Park of American Samoa. The U.S.
National Park Service is presently (2005) negotiating with village councils on Olosega to expand the park around that island.
The island forms the
Ofu County subdivision of the
Manua District. It has a land area of 7.215 km² (2.786 sq mi), and had an official population of 289 persons as of the
2000 census.
Olosega
Olosega Island is a remnant of the Sili
shield volcano, the
caldera of which may lie submerged off the north shore. The undersea eruption of 1866 was actually 3 km east of Olosega, on a
submarine ridge that extends eastsoutheast to nearby
Ta‘ū.
The island forms the
Olosega County subdivision of the
Manua District. It has a land area of 5.163 km² (1.993 sq mi), and had an official population of 216 persons as of the 2000 census.
There are two villages on Olosega: Olosega and
Sili. Sili now consists of but one standing residence after much of the village was destroyed by hurricanes (and subsequently abandoned). Nearly all of the population of Olosega now resides in Olosega village along the southwestern-facing shore.
References
★ Office of the Governor. 2004. ''Manu‘a ma Amerika''. A brief historical documentary. Manu‘a Centennial. 16 July 1904. 16 July 2004. Office of the Governor, American Samoa Government. 20 p.
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Ofu County and Olosega County, Manu'a District, United States Census Bureau
External links
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National Park Service map of the Manu‘a Islands
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Persistence of Coral Reefs Under Extreme Environmental Stress in American Samoa G. Piniak, C. Birkeland, and G. Garrison (2004). University of Hawaii.