Truman Proclamation on the Continental Shelf
The Truman Proclamation on the Continental Shelf, issued on September 28, 1945, established U.S. jurisdiction over the natural resources of the continental shelf adjacent to its coasts, while still respecting the rights of other nations to navigate over these waters. The proclamation emerged from concerns over fishing rights and natural resource access, particularly following World War II, and marked a significant shift in the United States' approach to maritime law. Prior to the proclamation, the U.S. adhered to a traditional three-mile limit for territorial waters, a stance that left many coastal states feeling vulnerable to foreign fishing activities.
The Proclamation laid the groundwork for subsequent claims and policies both domestically and internationally. It influenced not only U.S. relations with Latin American countries, which began asserting their own claims to offshore areas, but also established legal precedents regarding continental shelf rights that would be recognized by the International Court of Justice. Domestically, the proclamation initiated a complex interaction between federal and state jurisdictions over offshore resources, leading to significant legislation such as the Submerged Lands Act of 1953, which granted specific rights to coastal states like Texas and Florida while asserting federal control beyond certain limits. Overall, the Truman Proclamation reflects the evolving dynamics of national interests, resource management, and international maritime law in the mid-20th century.
Truman Proclamation on the Continental Shelf
Date September 28, 1945
Started by President Franklin Roosevelt, Jr., and championed by Secretary of the Interior Harold Ickes, the Truman Proclamation was a unilateral claim by the United States on the natural resources located in the continental shelf. Issues of federal versus state jurisdiction over offshore resources resulted in a compromise between the federal government and some coastal states. Although the proclamation negatively influenced U.S. relations with the Latin American states, it marked the beginning of international law on the continental shelf.
Also known as Proclamation 2667; Policy of the United States with Respect to the Natural Resources of the Subsoil and Sea Bed of the Continental Shelf
Locale United States
Key Figures
Harry S. Truman (1884-1972), thirty-third president of the United States, 1945-1953Harold Ickes (1874-1952), U.S. secretary of the interiorFranklin D. Roosevelt (1882-1945), thirty-second president of the United States, 1933-1945James Francis Byrnes (1879-1972), U.S. secretary of state, 1945-1947
Summary of Event
Before World War II broke out in 1939, some fishing states in the United States were concerned with the presence of foreign vessels fishing off their coasts, among them Japanese vessels in Bristol Bay, Alaska. Though the Japanese government agreed to ban Japan’s salmon-fishing activities in that area in 1938, the American fishing states remained dissatisfied with the traditional three-mile limit on exclusive coastal fishing, believing that U.S. jurisdiction should be extended to include the waters above the continental shelf, which extended farther.

A related incident in 1939 caught President Franklin D. Roosevelt’s attention. The Independent Exploration Company asked the Department of the Interior for permission to ascertain the presence of oil beyond the three-mile limit in the Gulf of Mexico. President Roosevelt proposed to the Department of the Interior the possibility of establishing national oil resources off the nation’s coasts. The proposal was turned down on the basis of international law, which stated that the seabed outside territorial waters was accessible by all and owned by no one. Not until 1943 was the issue revisited, and eventually the policy known as the Truman Proclamation on the Continental Shelf was formed in 1945.
The policy began with a May, 1943, memorandum from the General Land Office of the Department of the Interior stating that the continental shelf contained natural resources that the United States needed, was an important breeding ground for fish, and could serve as a hiding place for submarines. The memorandum also suggested drawing a line between domestic and international waters 100 or 150 miles from the shore. Immediately, Secretary of the Interior Harold Ickes brought the matter to President Roosevelt’s attention and proposed forming new concepts of territorial limits. Accordingly, the president asked the State Department to give consideration to mineral resources, fisheries, and extended jurisdiction offshore. An agreement was reached between the State Department and the Interior Department: The former would work on the fisheries statement and the latter on the continental shelf statement. Secretary Ickes proposed that the United States claim absolute sovereignty over the continental shelf and the waters above it. The State Department, however, was more concerned with rights of access for American vessels, fishermen, and aircraft in the vicinities of the coasts of other countries. In the final agreement, Ickes’s “sovereignty” was replaced by “jurisdiction.”
Ickes also wanted the proclamation to be announced immediately. President Roosevelt gave his approval to the matter on March 31, 1945; however, he wanted to have the proclamation publicized only after informal consultations with several countries. The countries notified of the proposed proclamation were Great Britain, Russia, Canada, Mexico, the Netherlands, Norway, France, Ireland, Denmark, Cuba, and Portugal. The issuance of the proclamation was further delayed when President Roosevelt died on April 12. His successor, Harry S. Truman, gave his verbal approval in early May. Another delay was caused by the fact that James Francis Byrnes had become secretary of state, and he needed time to become informed concerning the continental shelf matter. The proclamation was finally released on September 28, 1945.
Better known as the Truman Proclamation on the Continental Shelf, Proclamation 2667 asserted that the United States had jurisdiction over the natural resources in the continental shelf under the high seas contiguous to the coasts of the United States and its territories. According to the proclamation, other nations’ rights of free and unimpeded navigation of waters above the shelf were still respected, and the limit of U.S. territorial waters remained three miles seaward from the coast. Because the vertical dimension of the claim was not mentioned in the proclamation, a White House press release of the same date indicated that the proclamation applied to the submerged land out to a water depth of 100 fathoms (600 feet). Executive Order 9633, issued on the same day, placed the continental shelf’s resources under the jurisdiction and control of the secretary of the interior.
It should be noted that a related proclamation, Proclamation 2668, was issued the same day. This proclamation provided for the establishment of conservation zones for the protection of fisheries in certain areas of the high seas contiguous to the United States. In such areas, fished only by American nationals, the United States would establish regulations by itself. Where foreign fishermen also operated, such zones would be established under the international agreement with foreign states.
Significance
During a five-year period after the issuance of the proclamation, a number of states in Central and South America also began staking out unilateral claims of their own to offshore areas. While the continental shelf declaration of Mexico could be interpreted as consistent with the U.S. position, the stance taken by Argentina, Chile, and El Salvador was out of line with American policy. Argentina claimed both its continental shelf and the epicontinental sea above it, while Chile and El Salvador asserted sovereignty over a 200-mile zone. Their claims were based on at least two factors. First, the distribution of continental shelf areas was not uniform; in the case of these states, there was little continental shelf to be found. Second, some of these states wanted to limit the access of foreign fishing vessels and to control the depletion of fish stock in their adjacent areas.
Internationally, then, the Truman Proclamation negatively influenced U.S. foreign relations with the Latin American states. Though the American claim of the continental shelf made sense in view of American interests, it did not similarly make sense from the perspective of foreign states. It also required the United States to protest and combat their claims; in fact, these states accepted the U.S. view only under diplomatic pressure. On a positive note, the International Court of Justice eventually considered the Truman Proclamation as the starting point of the two concepts of international law relating to the continental shelf: delimitation by mutual agreement and delimitation in accordance with equitable principles.
Domestically, the matter of federal-state jurisdiction over offshore resources resulted in a compromise between the federal government and a number of coastal states. In 1947 and 1950, the U.S. Supreme Court gave the federal government full authority over the lands and natural resources in the submerged lands off the coasts. However, the Submerged Lands Act, enacted by Congress in 1953, granted the states that had brought the actions certain jurisdictional rights to offshore lands. Texas and Florida were granted a ten-mile limit and the control and development of oil and gas resources and exploration. Beyond this special limit and the usual three-mile limit applied in other states, resources in the seabed and subsoil were deemed to belong to the federal government. The Outer Continental Shelf Lands Act, enacted by Congress in the same year, gave the federal government the right to offer mineral leases on submerged lands beyond state jurisdiction.
Bibliography
Cicin-Sain, Biliana, and Robert W. Knecht. The Future of U.S. Ocean Policy: Choices for the New Century. Washington, D.C.: Island Press, 2000. This in-depth analysis of the evolution of U.S. ocean policy includes a discussion of the most important ocean and coastal issues facing the nation. A valuable guide for students and scholars of marine and coastal environment management and law.
Freestone, David, Richard Barnes, and David Ong, eds. The Law of the Sea: Progress and Prospects. New York: Oxford University Press, 2006. A critical review of the U.N. Convention on the Law of the Sea and its relationship to a wide range of developments that have occurred since 1982.
Murphy, John F. The United States and the Rule of Law in International Affairs. New York: Cambridge University Press, 2004. A textbook account of the procedures and processes of international law, including international law of the sea.