How did Swains Island become part of American Samoa?

Swains Island, a coral atoll located in the southwestern Pacific Ocean, was not originally part of the Samoan archipelago and was historically associated with the Tokelau Islands.1

The island was claimed in 1856 by the American trader Eli Jennings, and it remained the property of his family. Following a period from 1916 to 1925 when it was administered as part of the Gilbert and Ellice Islands, Swains Island was officially incorporated into the U.S. territory of American Samoa in 1925.12