After taking the Spanish position at Las Guasimas, Fifth Corps advanced up the road to Santiago unimpeded except by the atrocious condition of the Camino Real. Supply problems soon became a far greater threat to the U.S. Army than the Spanish, since the latter remained inside the Santiago defenses and gave no indication of any intent to counterattack. This was due largely to the fact that the US Navy had Santiago blockaded by sea while the Cuban Insurrectos had cut the city off from supplies by land, leaving the Spanish garrison progressively growing weaker from living on half rations.

General Shafter set about improving the American supply and communications lines while ordering his men not to attack until reinforcements arrived, but all that changed on June 28th when he got word that a Spanish relief column was on its way toward the city. He had to bring the Spanish to battle before they could be reinforced, and the first order of business was to make sure no such reinforcements could reach the city. To that end, Shafter approved General Henry L. Lawton’s proposal to march his division northward and capture the heavily-fortified village of El Caney on the road to Guantanamo. This would block any reinforcements from Guantanamo from reaching Santiago and would also secure Fifth Corps’ right flank. Lawton would then march 2nd Division southwestward to a flanking position on the San Juan Heights so that he could roll up the Spanish lines there when the rest of Fifth Corps attacked frontally later that morning. Lawton assured Shafter that El Caney would fall in less than two hours, so Shafter gave the order to delay the main attack on the Heights until after Lawton was in position on the Spanish flank.

Lawton failed to bring any support weaponry to the attack on El Caney other than one battery of light field guns. Those guns had little effect on the well-fortified village, so he maneuvered a brigade north of the village while a second would attack from the south and a third would begin in reserve. The town did not fall in two hours – not even close. The Spaniards in El Caney bravely held off Lawton’s entire division all day long, despite repeated dispatches from Shafter requesting Lawton to break off the attack and support the main effort against the San Juan Heights. Lawton felt that to comply would be to admit defeat, so he continued the attack until the Spanish finally fled El Caney late in the afternoon. Thus a small Spanish force kept an entire American division busy until after the attacks on San Juan and Kettle Hills were concluded.