The United States has some intriguing laws, but one of the lesser-known ones is related to the acquisition of unclaimed islands featuring guano, more commonly known as bird or bat poop. This law, known as the Guano Islands Act, was enacted in 1856. The Act allows U.S. citizens to take possession of unclaimed islands anywhere in the world, provided the islands are not occupied and are covered in guano. The purpose of this law was primarily economic. In the mid-19th century, guano was highly prized as an agricultural fertilizer due to its high content of nitrogen, phosphate, and potassium, essential nutrients for crop growth.
Under the Guano Islands Act, once a U.S. citizen discovers guano on an unclaimed island and takes peaceful possession of it, they can notify a U.S. district court, which then allows the United States to consider the island as a possession, at least temporarily. The discoverer has exclusive rights to mine the guano. The ownership and control of such islands, however, are subject to U.S. law, and the President of the United States maintains the authority to use the military to protect such interests.
Since its enactment, the Guano Islands Act has been the basis for American claims to dozens of islands in the Pacific and Caribbean regions. Notably, many of these islands are no longer controlled by the U.S. or deemed necessary, as the importance of guano as a resource has significantly diminished with the advent of modern synthetic fertilizers. Additionally, the realities of international law and sovereignty claims by other nations have often made the practical application of the Guano Islands Act complex.
Interestingly, the law is still technically in effect today, though it's rarely applied. It serves as a historical example of the lengths countries would go to secure valuable resources, a testimony to the age when the expansionist policies dubbed "Manifest Destiny" influenced much of U.S. foreign policy. In modern contexts, the Guano Islands Act is occasionally mentioned in discussions about U.S. law and territorial claims, serving more as a curiosity and a snapshot of a bygone era rather than as a practical piece of legislation in today's political landscape.
