List the steps required for the US Federal Government to purchase land from a foreign country

The United States has acquired new territory through cession, purchase, and occupation, according to the U.S. Department of the Interior's Office of Insular Affairs.[3] The U.S. also leased the Panama Canal Zone from 1903 to 1999. The country's first and largest territorial acquisition was the Louisiana Purchase in 1803 for $10 million; it nearly doubled the landmass of the original 13 states. In 1947, the Mariana Islands, Caroline Islands, and Marshall Islands became the most recent U.S. territorial acquisitions, as of August 2019.

The cheapest acquisition by purchase was of Alaska for $12 per square mile. The most expensive acquisition by purchase was of the U.S. Virgin Islands for $183,824 per square mile.

The territories gained by the U.S. through occupation were primarily small islands in the Pacific Ocean and the Caribbean Sea. The Guano Islands Act of 1856, which was designed to assist American farmers by making guano (dried sea bird excrement) easier to mine for use as fertilizer, authorized such occupations.[4]

Historical