The coastal town sprang out from an Austronesian settlement in the early 16th century when indio natives managed to escape colonial tyranny from the Spaniards. The settlement was then known as Sibala, named after the river that ran through the coastal village. In 1570, however, the settlement was seized by Spanish colonial officials and the guardia civil took full control of the village. It later flourished into a bigger and prosperous town and was renamed after its designated patron saint La Nuestra Señora del Pilar ( Our Lady of the Pillar). Several friars and missionaries were assigned to preach in the town since then until it later received its permanent parish priest.

There had been a famous resistance called the Battle of Balisong during the Philippine Revolution in the 19th century as an attempt to overthrow Spanish officials in the municipality led by local revolutionaries Juan Arce and Dalmacio Patricio.

Today, an iconic 12-foot landmark of the Virgin Mary is visible at a mountaintop in Brgy. Dulangan, built by an affluent Chinese-Filipino merchant in honor of the town's patron saint, which is also said to have conducted miraculous powers to its devotees several times.

The town celebrates its annual feast along with the coming of the sacred Santisima Trinidad (The Holy Trinity), an early 18th century wooden figurine from Mexico found by local fishermen in the shores of the town during the British invasion of the Philippines in 1762. The figurine was said to be brought over to the Pacific by a Galleon trading ship from the port of Acapulco, Mexico which was destroyed by British warships during its route in Luzon and was washed off to the coast of Pilar. It is now still visible at the altar of the town's church, the Parish of the Most Holy Trinity.

The town is also known for its rich local heritage in mythology and folklore of legends and supernaturalism. The Legend of the Golden Shiptells the myth of a beautiful fairy that dwells in the caves of the town's mountainous forests and seduces young men every full moon wherein an illusionary lake appears inside the cave of Balisong and the mistress disappears with her victims in a golden ship along with the fading of the lake at sunrise.