By late spring 1941, with the war in Europe a year and a half old, Britain’s back was against the wall and Prime Minister Winston Churchill asked President Franklin D. Roosevelt to send American troops to Iceland to replace the British Garrison there.
Roosevelt agreed, and on 5 June directed the Chief of Naval Operations, Admiral Harold R. Stark, to have a Marine brigade ready to sail in 15 days’ time.
The 6th Marine Regiment was diverted from joining the 1st Marine Division in the Caribbean, to Charleston to be the nucleus of the 1st Provisional Marine Brigade. The brigade was formed on 16 June, the day following the arrival of the 6th Marines in Charleston, and commanded by Brigadier General John Marston. Admiral Stark’s mission statement was simple and direct: In cooperation with the British garrison, defend Iceland against hostile attack.
Six days after the 16 June activation, the 4,095 Marines sailed on 22 June for the North Atlantic. Added to the convoy at Charleston were two cargo ships and two destroyers. It was met outside the harbor by an impressive force of warships and escorts. When the entire convoy began its move towards the North Atlantic, it consisted of 25 vessels, including two battleships and two cruisers.
The brigade reached the capital city of Reykjavik, Iceland, on the morning of 7 July, where it would remain until sailing for home on 8 March 1942. By the end of 1942, some of the Iceland Marines and sailors were battling the Japanese on Guadalcanal in the South Pacific, and many others went on to serve with distinction in the other major Navy/Marine Corps amphibious assaults of the Pacific War.