The Legislative Districts of Isabela, namely the first, second, third, fourth districts, are the representations of the Province of Isabela and the independent city of Santiago in the Philippine House of Representatives. The province was represented as a lone legislative district until 1972. It was part of the representation of Region II from 1978 to 1984, and from 1984 to 1986, it elected 3 assemblymen at-large. In 1986, it was redistricted into four legislative districts.
On December 14, 2016, all the four Representatives of the Province of Isabela; Reps. Albano, Go, Dy, and Aggabao, plus two Party-list Representatives with ties to the province; Reps. Panganiban (ANAC-IP), and Ty (LPGMA) filed House Bill 4692 where it proposes to create two more additional Legislative Districts in the province. The Bill is pending the House, and it has yet to be filed in the upper chamber: Philippine Senate.