Cabagan, officially the Municipality of Cabagan (Ibanag: Ili nat Cabagan; Ilocano: Ili ti Cabagan; Tagalog: Bayan ng Cabagan), is a 1st class municipality in the province of Isabela, Philippines. According to the 2020 census, it has a population of 53,897 people.

Etymologically, the name Cabagan may have originated from the native word bag or bajaque, not because “G-strings” were used here or made in Cabagan, but most probably because there were stores in the village. Cabagan could have also been derived from the word cabbagang, meaning “pilgrim” or “stranger”. Based on the fact that Cabagan at the time was in constant contact with members of the “pagan tribes” from southern Isabela as well as with the “Kalingas”, of the neighboring Cordillera mountains.