The Puerto Rico campaign was the American military sea and land operation in Puerto Rico during the Spanish–American War, which resulted in the invasion, occupation, and annexation of the archipelago and island by the United States, and the cession of said territory by Spain. The offensive began on May 12, 1898, when the United States Navy attacked the capital, San Juan. Though the damage inflicted on the city was minimal, the Americans were able to establish a blockade in the city's harbor, San Juan Bay. On June 22, the cruiser Isabel II and the destroyer Terror delivered a Spanish counterattack, but were unable to break the blockade and Terror was damaged.
The land offensive began on July 25, when 1,300 infantry soldiers led by Major General Nelson A. Miles disembarked off the coast of Guánica. After winning the first skirmish, the Americans advanced to Coamo, where they engaged Puerto Rican and Spanish troops in battle. With two defenders and four Americans dead, the defenders retreated. The United States forces were able to seize control of Fajardo on August 1, but were forced to withdraw on August 5 after a group of 200 Puerto Rican–Spanish soldiers led by Pedro del Pino counterattacked, while most civilian inhabitants fled to the nearby lighthouse. The Americans encountered more opposition as they advanced towards the main island's interior. They engaged in two crossfires in Guamanà River and Coamo, both of which were inconclusive as the allied soldiers retreated. A battle in San Germán concluded in a similar fashion with the Spanish retreating to Lares.