On July 1, 1898, the U.S. Expeditionary Forces under assaulted the Spanish defenses of Santiago, where the Spanish squadron lay protected in the harbor. After sending one division to attack Spanish defenses, Major General Shafter ordered the Fifth Corps to attack San Juan Heights, where General Linares had established a forward defensive line 4,000 yards long anchored on San Juan Hill, the largest elevation in the area.
In the difficult terrain below the heights, U.S. troop camps, located by their artillery's smoke and their observation balloon, came under Spanish fire. The main attack began at 1:00 P.M. The key to the assault on San Juan Hill by a U.S. infantry division was the effective fire of a battery of three Gatling guns that swept the summit and forced most of the Spanish defenders to flee as the infantry in some disarray secured the heights.
To the right, meanwhile, elements of a dismounted cavalry division moved against Kettle Hill. Without benefit of weapons or the Gatling gun, standing in the face of heavy enemy fire, the troopers of two regular army cavalry regiments, the First and the Ninth (the second one of the army's black regiments), and the First U.S. Volunteer Cavalry