Answer:
The province of La Union was formed in 1850 when the Spanish colonial government of Governor-General Antonio Maria Blanco merged the southern towns of Ilocos Sur, the northern towns of Pangasinan, and the western towns of Benguet to the east. Source: PIA The natives of what is now La Union were already trading with the Japanese Spaniards came to the Philippines; the area of Agoo was then known as "Puerto de japon." Captain Juan de Salcedo explored the region in 1572, followed by Augustinian missionaries who founded the towns of Balaoan, Bauang, and Agoo in the late decades of the 16th century. The province was created on March 2, 1850 out of towns then belonging to Ilocos Sur and Pangasinan. Luciano Almeda headed the provincial government for a time during the Philippine Revolution while General Manuel Tinio occupied San Fernando in May 1898.
