The history of the United States Coast Guard goes back to the United States Revenue Cutter Service, which was founded on 4 August 1790 as part of the Department of the Treasury. The Revenue Cutter Service and the United States Life-Saving Service were merged to become the Coast Guard per 14 U.S.C. § 1 which states: "The Coast Guard as established January 28, 1915, shall be a military service and a branch of the armed forces of the United States at all times." In 1939 the United States Lighthouse Service was merged into the Coast Guard. The Coast Guard itself was moved to the Department of Transportation in 1967, and on 1 March 2003 it became part of the Department of Homeland Security. However, under 14 U.S.C. § 3 as amended by section 211 of the Coast Guard and Maritime Transportation Act of 2006, upon the declaration of war and when Congress so directs in the declaration, or when the President directs, the Coast Guard operates as a service in the Department of the Navy.

The United States Revenue Cutter Service was established by an act of Congress on 4 August 1790 as the Revenue-Marine upon the recommendation of Secretary of the Treasury Alexander Hamilton to serve as an armed customs enforcement service. As time passed, the service gradually gained missions either voluntarily or by legislation, including those of a military nature. It was generally referred to as the Revenue-Marine until 31 July 1894, when it was officially renamed the Revenue Cutter Service. The Revenue Cutter Service operated under the authority of the U.S. Department of the Treasury. On 28 January 1915, the service was merged by an act of Congress with the United States Life-Saving Service to form the United States Coast Guard.