In the early part of 1921, immigrants from Central Luzon pioneered by the families of Nano, Fabrigas and Espanol came into this large strip of virgin lands along the Pacific Coast via the jungle of the Sierra Madre Mountains.

The Municipality of Dipaculao was accidentally created when while the Ilongots were having festivities of thanksgiving to commemorate the abundance of hunting and harvesting, "Dipac," the Ilongot Chieftain was drunk with "Basi" and "Tuba", a kind of native, fell on the ground. The Ilocanos who were present saw him fell shouted." Dipac naulaw", (Dipac got Dizzy), hence born the name Dipaculao.

Dipaculao was formerly a barrio of the Municipality of Baler. It was made into an independent Municipality on November 27, 1950 thru Executive order No.375 by the late President Elpidio Quirino. The late Anacleto Mijares was the first Municipal Mayor by appoinment who administered the transition of the Municipality.

The Municipality of Dipaculao was initially composed of 17 barangays, viz: Poblacion, Mijares, Ipil, Salay, Bayabas, Mucdol, Buenavista, Diarabasin, Dibutunan, Borlongan, Dianed, Dinadiawan, Diamanen, Puangi, Lobbot, Toytoyan, and Gupa. At present, the municipality has twenty-five (25) barangays as a result of the addition of eight (8) more barangays including the following: Laboy, Lipit, Maligaya, Sapang Kawayan, Dimabuno, Ditale, and Calaocan, and the split into two (2) seperate barangays of the Poblacion, the North Poblacion and the South Poblacion.

In 1952 the late Juan Roque assumed office of the first elected Mayor of Dipaculao. The late Florentino Velasco succeeded him from 1954 to 1980. After the retirement of the undefeated Mayor Velasco, who serves for twenty-six (26) years, his son Salvador Velasco succeeded him. After the EDSA revolution on 1986, an appointed office-in-charge, Mr. Crispin Paulino replaces Mayor Salvador Velasco. On 11 may 1982, a local election was held and gave Mayor Velasco another opportunity to administer the affairs of the municipality of Dipaculao, winning by overwhelming votes. He holds the position up to 1998. The synchronized local and national election in 1998 resulted to the change of administration where the Hon. Danilo A. Tolentino was elected as the municipal Mayor of Dipaculao.