By the middle of the 19th century, Sarapsap was the most progressive and prosperous town in Northern Zambales, attracting even the attention of Spanish authorities that in 1860, Juan Alaminos y Vivar,the Spanish Governor-General of the Philippines, visited it. Being a democratic administrator, the governor-general captured the hearts of the inhabitants and in 1887, under the leadership of Captain Domingo Montemayor, Sarapsap was renamed 'Alaminos', in honor of the governor-general. The town expanded in commerce, transportation and education. Many enterprising young men from other towns came to set up business or a profession, marry and live in Alaminos.
Katipuneros in Alaminos
During the period of struggle against the Spanish rule, Spanish soldiers raided the houses of the town elite and arrested all the town officials led by Don Florentino Montemayor. Their unlawful incarceration prompted some Alaminians to join the Katipunan movement. And though the town officials were eventually released, the revolutionary movement had taken root. Roman Manalang, a native of Castillejos, Zambales and married to an Alaminos lass, led the revolutionaries of Alaminos, with the assistance of Gen. Mauro Ortiz, Col. Jose Montemayor Jimenez and a selected group of young officers. The rebellion spread quickly as Alaminos was put under martial law as were all towns in Zambales but were met with great resistance led by the counter-attack plan by the Spaniards, led by General Monet.
With the surrender of Emilio Aguinaldo and the signing of the Treaty of Paris between Spain and the United States, the local leaders capitulated. In 1903, the American colonial government called for a province-wide meeting of leaders. In that meeting, nine towns of Northern Zambales, including Alaminos, were made part of Pangasinan. The first Municipal President to be elected by the town people of Alaminos was Don Francisco Reinoso.
Following the writing of a Commonwealth Constitution, Pangasinan was represented in the national legislature by five district representatives. There was relative peace until the Pacific war broke out. During the ensuing resistance movement against the Japanese, many groups in Pangasinan were involved in the guerilla movement. Dr. Pedro Braganza, an officer under Col. Lapham of Central Luzon was assigned to the 37th Infantry Battalion in the Ilocos region, formed of mostly Northern Luzon guerillas who fought and won in the battle of Bessang Pass.
The postwar years saw Alaminos rebuilding itself and energizing its economy which virtually was at a standstill during the war. In 1991, it was reclassified from a fourth to a third class municipality. In 1997, it was reclassified from third class to a first class municipality, as it posted a 338.5% increase in its gross income.