History
According to folk legend, the name Casiguran was obtained from the word Kasiguruhan which means "safety" or "assurance". Safety means defense - a fortress or sanctuary for sailing ships during stormy weather. Another legend says that if an unmarried stranger comes to the place, he unavoidably falls in love with someone and gets married and most of the time stays for good.
Casiguran is the most urbanized town among the Northern municipalities of Aurora. It has a public hospital and a private airstrip.
The town of Casiguran was originally under the Province of Nueva Vizcaya. The date of its establishment could not be determined, although there is an unproved claim that it was founded in 1609.
Sometime in 1905 to 1908 the boundary of Quezon Province was extended to the north, making the municipality of Casiguran a part of Quezon.Casiguran was founded by the Spanish Missionaries on June 13, 1609. Prior to their arrival, early settlers were the Dumagats and Aetas, followed by migrants from other areas of the country.

A Kasiguranin language evolved out of these dialects. In 1942, Japanese Occupation forces landed in the town of Casiguran. In 1945, the town of Casiguran was liberated by Allied Philippine Commonwealth troops and recognized guerrilla units during the Battle of Casiguran at the end of World War II
When the Philippines became independent in 1946, Aurora was still part of Tayabas Province (now Quezon Province) and Casiguran was a lone northern town. Its political jurisdiction is bounded on the north by the province of Isabela, on the west by Quirino Province, and on the south west by barangay Dinadiawan, which was then the boundary between Baler and Casiguran.
In 1959 and 1966, the barrios of Dilasag and Dinalungan, which were part of Casiguran and situated on its northern and southwestern portions, were created municipalities.
A total of 34 local leaders administered the municipality of Casiguran since its establishment as a community and creation as a municipality. At present, the incumbent municipal mayor (34th) is Hon. Reynaldo TehBitong.