Kingman Reef is a small, uninhabited atoll located about 1,000 miles north of Tahiti. The United States officially annexed Kingman Reef on May 10, 1922, under the Guano Islands Act, which allowed the U.S. to claim uninhabited islands containing guano deposits. Guano, primarily bird excrement, was seen as a valuable resource for fertilizer and was thus economically important. The annexation was a strategic move to extend U.S. control and influence in the Pacific Ocean during a time when global powers were competing for resources and territory.

Prior to the annexation, Kingman Reef had been known to mariners and occasionally visited by ships; however, its strategic value became clearer after the U.S. took formal control. The reef was primarily used for military and navigational purposes, forming part of the U.S. Pacific strategy in the years to come. Its status as an uninhabited territory meant that it did not immediately impact civilian lives but instead held promise for future military and commercial interests.

Annexing Kingman Reef was part of a larger pattern of U.S. territorial expansion during the early 20th century. This period saw a heightened interest in the Pacific region as the U.S. began to emerge as a significant global power. From then on, the reef contributed to the network of U.S. possessions in the central Pacific, which would play roles in both commercial shipping routes and military strategy, particularly during World War II when the Pacific theater became a focal point of combat.