Guano Act
Whenever any citizen of the United States discovers a deposit of guano on any island, rock, or key, not within the lawful jurisdiction of any other Government, and not occupied by the citizens of any other Government, and takes peaceable possession thereof, and occupies the same, such island, rock, or key may, at the discretion of the president, be considered as appertaining to the United States.
The Guano Act (formally the Guano Islands Act) is a U.S. law enacted in 1856. It enables U.S. citizens to take possession of unclaimed islands containing deposits of guano, the excrement of seabirds and bats. Most of the islands claimed by the U.S. under the act have been withdrawn. Islands still claimed under the Guano Act include the Midway Islands (namesake of the pivotal WWII battle) and Howland Island (the island Amelia Earhart was searching for when she disappeared). Leicester Hemingway (brother of Ernest) unsuccessfully attempted to use the Guano Act to establish a new country called the Republic of New Atlantis, which would have been located on a bamboo raft anchored to an old Ford engine block just outside the territorial waters of Jamaica.