On 18 June the US 9th Infantry Division reached the west coast of the peninsula, isolating the Cherbourg garrison from any potential reinforcements. Within 24 hours, the 4th Infantry, 9th and 79th Infantry Divisions were driving north on a broad front. There was little opposition on the western side of the peninsula and on the eastern side, the exhausted defenders around Montebourg collapsed. Several large caches of V-1 flying bombs were discovered by the Americans in addition to a V-2 rocket installation at Brix.