Rose Atoll, sometimes called Rose Island or Motu O Manu by people of the nearby Manu'a Islands, is an oceanic atoll within the U.S. territory of American Samoa. It is an uninhabited wildlife refuge. It is the southernmost point in the United States.Just west of the northernmost point is a channel into the lagoon, about 40 meters wide. There are two islets on the northwestern rim of the reef, larger Rose Island in the east (3.5 m high) and the non-vegetated Sand Island in the north (1.5 m high).
Rose Atoll contains the largest populations of giant clams, nesting seabirds and rare reef fish in all of American Samoa. The fish population is unique from the rest of the region due to a high concentration of carnivorous fish and low concentration of herbivorous fish. Almost 270 different species of fish have been recorded in the last 15 years.
Tuna, mahi-mahi, billfish, barracuda and sharks reside outside the lagoon. In deeper waters, tunicate and stalked crinoid have been spotted by scuba expeditions. Sea mammals such as the endangered humpback whale and the stenella genus of dolphin also use the waters.