'Galloper' was a British naval undertaking to remove British forces from Iceland as the protection of the island was transferred to forces of the neutral USA following an agreement of 7 July 1941 (July 1941).

On 1 July Rear Admiral David McD. Lebreton’s US Task Force 19 departed Argentia 1 as escort for the movement to and landing at Reykjavik, the capital of Iceland, of the 4,100 men of Brigadier General John Marston’s 1^st Marine Brigade (Provisional) in the transports William P. Biddle, Fuller, Heywood and Orizaba, and the freighters Arcturus and Hamul.

After the operation had been completed, TF19 returned to Argentia between 12 and 19 July. Between this latter day and 13 September, Admiral Ernest J. King’s Atlantic Fleet established TF1 for the defence of Iceland and to protect convoys to and from the island. A task group consisting of fleet carrier Wasp, heavy cruisers Quincy and Vincennes, and destroyers O’Brien and Walke delivered Curtiss P-40 fighters to Iceland, the fighters being flown off the carrier without loss at sea. Among the units employed in convoy service to Iceland were Destroyer Squadron 7 (Benson, Niblack, Hilary P. Jones, Plunkett, Mayo, Madison, Cleaves, Charles F. Hughes and Lansdale), Destroyer Squadron 11 (Grayson, Roe and Sampson), Destroyer Squadron 30 (Dallas, Greer, Tarbell, Cole, Bernadou, Lea, Ellis and Upshur) and Destroyer Division 62 (McCormick, Sturtevant, Reuben James and Bainbridge).

From 6 August the Consolidated PBY and Martin PBM Mariner flying boats of the US Navy’s VP-73 and VP-74 squadrons operated from Reykjavik and the Hvalfjörður respectively.

Early in 1942 the US Marine Corps transferred responsibility for the garrisoning of Iceland to the US Army so that its men could be redeployed to the Pacific theatre.