Guano Islands Act

The Guano Islands Act (11 Stat. 119, enacted August 18, 1856, codified at 48 U.S.C. ch. 8 §§ 1411-1419) is a United States federal law passed by the U.S. Congress that enables citizens of the United States to take possession of unclaimed islands containing guano deposits. The islands can be located anywhere, so long as they are not occupied and not within the jurisdiction of another government. It also empowers the President of the United States to use the military to protect such interests and establishes the criminal jurisdiction of the United States in these territories.

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 Act continues to be part of the law of the United States. The most recent Guano Islands Act claim was made to Navassa Island, however, the claim was discarded because a court ruled the island was already under American jurisdiction (a claim Haiti disputes).

In the 1840s, guano came to be prized as a source of saltpeter for gunpowder as well as an agricultural fertilizer. The United States began importing it in 1843 through New York. By the early 1850s, the U.K. imported over 200,000 tons a year, and U.S. imports totaled about 760,000 tons. The "guano mania" of the 1850s led to high prices in an oligopolistic market, attempts of price control, fear of resource exhaustion, and eventually the enactment of the Guano Islands Act 1856 in August 1856. The Act enables U.S. citizens to take possession of unclaimed islands containing guano for the U.S., and empowering the President to send in armed military to intervene. This encouraged American entrepreneurs to search and exploit new deposits on tiny islands and reefs in the Caribbean and in the Pacific.

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