On November 10, 1775, the Continental Congress meeting in Philadelphia passed a resolution stating that "two Battalions of Marines be raised" for service as landing forces with the fleet. This resolution, established the Continental Marines and marked the birth date of the United States Marine Corps.   In World War I the Marine Corps distinguished itself on the battlefields of France as the 4th Marine Brigade earned the title of "Devil Dogs" for heroic action during 1918 at Belleau Wood, Soissons, St. Michiel, Blanc Mont, and in the final Meuse-Argonne offensive.

During the two decades before World War II, the Marine Corps began to develop in earnest the doctrine, equipment, and organization needed for amphibious warfare. The success of this effort was proven first on Guadalcanal, then on Bougainville, Tarawa, New Britain, Kwajalein, Eniwetok, Saipan, Guam, Tinian, Peleliu, Iwo Jima, and Okinawa. By the end of the war in 1945, the Marine Corps had grown to include six divisions, five air wings, and supporting troops. Its strength in World War II peaked at 485,113. The war cost the Marines nearly 87,000 dead and wounded and 82 Marines had earned the Medal of Honor.