The Corn Islands, along with the eastern half of present-day Nicaragua, were a British protectorate from 1655 until 1860, a period when the region was called the Mosquito Coast. At one time, the islands were frequented by Caribbean pirates. The Nicaraguan government annexed the region in 1894.
Under the Bryan–Chamorro Treaty of 1914, the islands were leased to the United States for a period of 99 years. The terms of the lease made the Corn Islands subject to the sovereignty of the United States. The lease notwithstanding, the United States never maintained a significant presence in the islands. The right of the United States to use of the islands remained until April 25, 1971, when the lease was officially terminated by the denunciation of the Bryan-Chamorro Treaty on July 14, 1970, under the presidency of Anastasio Somoza Debayle.