Adm. Cervera's fleet had taken refuge (29 May 1898) in Santiago Bay, and the American Navy had asked the Army to reduce the defenses guarding the entrance. The War Department, eager to get the Army into action, directed Maj. Gen. William R. Shafter to embark his loosely organized V Corps, which had been assembled around Tampa, and sail for Cuba. After many delays, and in an atmosphere of the utmost confusion, the embarkation of some 17,000 men began on 11 June 1898, lasting four days. On 20 June the convoy reached a point off Santiago, but it was two days before Shafter could make up his mind where to land the troops. Rear Adm. William T. Sampson wanted them to land near the entrance of the bay, where a powerful fort dominated the area, and to storm the positions guarding the sea approaches. Shafter considered this plan too dangerous and followed the advice of Gen. Calixto Garcia, a Cuban insurgent leader, who recommended Daiquiri, 18 miles east of Santiago Bay, as a landing site.
Santiago, 22 June - 11 July 1898. The campaign got under way with a confused landing operation which, fortunately for the Americans, was unopposed. About 6,000 troops were landed on the first day, 22 June, and the march on Santiago began at once. On the following day Brig. Gen. Henry W. Lawton, commanding the forces ashore, easily captured the town of Siboney. As Lawton paused to reorganize, Brig. Gen. Joseph W. ("Fighting Joe") Wheeler stole a march on him by pushing ahead toward Santiago with his dismounted cavalry division. At Las Guasimas Wheeler ran into a sharp fight with the rear guard of a retiring Spanish force. The Americans suffered a loss of 16 killed and 52 wounded, and the Spaniards lost 12 killed and 14 wounded. This action only slightly delayed the main advance, since the Spaniards had not planned to make a determined stand until the Americans reached Santiago's outer defenses.
The most important of those defenses were along a series of ridges known collectively as San Juan, and in the village of E1 Caney to the north. Shafter decided to attack E1 Caney first and then follow with a frontal assault on the San Juan positions. General Lawton was assigned to take El Caney, which was defended by about 500 Spaniards, and Maj. Gen. Jacob F. Kent was in charge of a larger force assigned to take the San Juan position, which was held by about 1,200 Spaniards. Lawton's and Kent's attacking forces totaled some 8,000 men.
Shafter launched his attack on 1 July 1898. After considerable confusion and some temporary reverses, Kent's forces stormed and took the Spanish positions on the southern half of the ridge, while dismounted cavalry forces under General Wheeler took the northern end, including Kettle Hill where Lt. Col. Theodore Roosevelt and his "Rough Riders" distinguished themselves. The attack on E1 Caney made little headway at first against determined Spanish resistance, but success was finally achieved after the supporting artillery was moved forward to positions where it could place effective fire on the enemy. The Spanish forces dropped back half a mile to a second line of defense, and except for a heavy exchange of artillery fire on 2 July there was no more fighting. In the engagements at San Juan and E1 Caney there were 1,475 American and more than 550 Spanish casualties.
On 3 July 1898 Admiral Cervera attempted to escape from Santiago Bay with his fleet. A dramatic running fight with the American fleet ensued. All the Spanish ships were destroyed, with a loss of about 600 men. The Americans lost only one man killed and one seriously wounded.
Following Cervera's disaster, Gen. Jose Toral, defender of Santiago, where near-famine conditions existed, entered into negotiations with General Shafter. On 16 July he signed terms of surrender, which provided for the unconditional surrender of 11,500 troops in the city and some 12,000 other troops stationed elsewhere in the province of Santiago.
Puerto Rico, 25 July - 13 August 1898. After the fall of Santiago General Miles took personal charge of an expedition to Puerto Rico. His force of about 3,000 men landed at Guanica on 25 July 1898, and an additional force under Maj. Gen. John R. Brooke landed at Guayama. Four columns of American troops quickly overran the island. There was some light skirmishing in which a few Americans were wounded, but the population as a whole received the Americans with enthusiasm.
Manila, 31 July - 13 August 1898. The Manila campaign was a sequel to the first naval engagement of the war. On 1 May 1898 a small American squadron under Comdr. George Dewey completely destroyed a Spanish naval force in Manila Bay. To take the city of Manila, Dewey needed ground forces; he therefore sent a request to Washington for 5,000 troops. Meanwhile he blockaded the port and encouraged Filipino insurgents, led by Emilio Aguinaldo, whom Dewey had brought from exile in China, to besiege the city pending the arrival of American troops. Aguinaldo, who had previously led an insurrection against Spanish rule, hoped for recognition of his Philippine Republic. While waiting the arrival of ground forces, Dewey was faced with delicate diplomatic problems as English, German, and French naval forces arrived, ostensibly to protect their nationals in the islands, but also to be on hand to pick up any loose territory in case the United States decided against taking control after the collapse of Spanish power.
The War Department responded eagerly to the request for ground forces, and had sent about 11,300 troops to Manila under the command of Maj. Gen. Wesley Merritt by 25 July. The Spaniards in Manila indicated a willingness to surrender to the Americans, but not to the Filipinos, since they did not want the city exposed to undisciplined native insurgents after capitulation. Such an arrangement was agreeable to tee Administration in Washington, which by this time was planning to take control of the Philippines. Dewey and Merritt accordingly persuaded the Filipinos to let only Americans make the final assault on Manila, at the same time they quietly made arrangements with the Spanish authorities for what was planned to be a noisy but bloodless capture of the city. The operation began as planned on 12 August 1898, but a few bands of Filipinos became mixed with the advancing troops, and some uncontemplated fighting took place in which 5 Americans were killed and 35 wounded. Eventually the firing and confusion were reduced sufficiently to permit the Spaniards to surrender to the Americans. Formal articles of capitulation were signed on 14 August 1898. Total American losses during the operations in the Philippines were 18 killed and 109 wounded. Filipino units that had entered Manila were persuaded to leave, but subsequently Aguinaldo led a rebellion against American rule.