The Republic of the Marshall Islands is a sovereign nation in "free association" with the United States. After more than a decade of negotiation, the Marshall Islands and the United States signed the Compact of Free Association on June 25, 1983. The people of the Marshall Islands approved the compact in a UN-observed plebiscite on September 7, 1983. The U.S. Congress subsequently approved the compact, adding several amendments which were accepted by the Government of the Marshall Islands and the compact entered into force on October 21, 1986.

Under the compact, the United States has full authority and responsibility for security and defense of the Marshall Islands, and the Government of the Marshall Islands is obligated to refrain from taking actions that would be incompatible with these security and defense responsibilities. The duration of the Compact's original economic provisions was 15 years (ending in 2001). The provisions were subsequently extended though September 2003 while an Amended Compact was negotiated. That Compact, modifying the economic and immigration provisions of the original, was signed in April of 2003. It has been ratified by the Government of the Marshall Islands, and will go into effect when implementing legislation and ratification is completed in the U.S.

The Department of Defense, under a subsidiary government-to-government agreement of the original compact, has use of the lagoon and several islands on Kwajalein Atoll. The atoll consists of approximately 90 islets around the largest lagoon in the world. The original agreement allowed the United States continued use of the U.S. Army Kwajalein Atoll (USAKA) missile test range until 2016. An amendment to that agreement, extending U.S. rights until 2066 with an option until 2086, was negotiated in conjunction with the Amended Compact. Another major subsidiary agreement of the original compact provides for settlement of all claims arising from the U.S. nuclear tests conducted at Bikini and Enewetak Atolls from 1946 to 1958. Under the terms of free association, more than 40 U.S. Government agencies such as the Federal Aviation Administration, U.S. Postal Service, the Small Business Administration, and the Federal Emergency Management Agency operate programs or render assistance to the Marshall Islands.

The United States and the Marshall Islands have full diplomatic relations. The Marshall Islands have expressed an interest in attracting U.S. investment.

The U.S. Embassy in the Marshall Islands is located on Long Island, Majuro (tel. 692-247-4011, fax 692-247-4012). Mailing Address: P.O. Box 1379, Majuro, MH 96960-1379.