Ilagan

Ilagan, (Ibanag: Siudad nat Ilagan; Ilokano: Siudad ti Ilagan; Filipino: Lungsod ng Ilagan), officially the City of Ilagan, is a 2nd class city and capital of the province of Isabela, Philippines. According to the 2015 census, it has a population of 145,568 people ^[3] making it the most populous city in the province.

With a total land area of 116,626 hectares (288,190 acres), it is the largest city in the island of Luzon and the fourth largest city in land area in the Philippines, after Davao City, Puerto Princesa and Zamboanga City.^[6] It holds the title as the most number of voters in the province with 88,413 voters.

Ilagan was a first class municipality before it become a city.

https://en.wikipedia.org/wiki/Ilagan