Pinili was established as a town on January 1, 1920 by virtue of Executive Order No.92 s.1919, which was signed by the governor general on December 20, 1919.

The place was formerly covered by a thick forest where wild animals abound. In 1920, at the height of the Filipino-American War, the rebel priest, Monsignor Gregono Aglipay, fled to the thick forest with several of his men and formed his sandatahan, to fight against the Americans who invaded the province. The Filipino soldiers under his command were weak in military tactics, and almost outnumbered by the enemies. To protect soldiers from the attack of the invaders, Monsignor Aglipay ordered some of his men to climb the tallest tamarind tree on top of the hill to watch for the coming of the American forces. When the watchers saw that there was something unusual they reported it to the hiding soldiers, so that they would be ready to fight. This was how the place was used during the war. For further protection, the priest ordered the settlers to build their houses newer to each other.