Isabela, officially the City of Isabela (Zamboangueño: Ciudad de Isabela; Filipino: Lungsod ng Isabela), and often referred to as Isabela City, is a 4th class city and the capital of the province of Basilan, Philippines. It is also colloquially known as Isabela de Basilan to differentiate the city's name from the province of Isabela on Luzon island. While administratively the island province of Ba
silan is part of the Autonomous Region in Muslim Mindanao (ARMM), Isabela City itself is in not part of this region and is placed under the Zamboanga Peninsula region. On December 27, 1973, President Marcos issued Presidential Decree No. 356, converting the City of Basilan into the Province of Basilan "to provide the close government attention and for the purpose of spurring its growth". Another Presidential Decree numbered 593 dated December 2, 1974, amended P.D. 356. The law not only defines the City's territory but also provided that the capital of Basilan shall be the Municipality of Isabela. It also created ten (10) Municipalities to comprise the new Province of Basilan. Presidential Decree No. 593 was later amended by Presidential Decree No. 840 dated December 11, 1975, reducing the number of municipalities to seven (7) in order to render its " territorial portion more complementary to the size of the area and more responsive to pacification, rehabilitation and total development of the province". The municipalities specified in the said amendment were the following: Isabela, Lamitan, Tuburan, Tipo-Tipo, Sumisip, Maluso and Lantawan, of which five (5) municipalities are now in existence. It also provided for the absorption of the territorial jurisdiction of the City of Basilan into the Municipality of Isabela with its poblacion as the capital seat of the province. Before Basilan was converted to a province, it had three regular municipalities, Isabela, Lamitan, and Maluso which are districts of the city of Basilan. Nanquil was appointed Military Governor, the city of Basilan was still functioning under Mayor Brown until December 31, 1975 due to its territorial boundary dispute with the Province of Basilan. By virtue of Republic Act No. 9023 Isabela was granted Cityhood, with said grant having been ratified by Isabela's residents on a plebiscite held April 25, 2001. Isabela's first City Mayor then was Luis Rubio Biel II, the sitting Municipal Mayor elected in 1998. On November of the same year, Isabela City's residents roundly rejected inclusion into the expanded Autonomous Region in Muslim Mindanao (ARMM), and have since remained under the administrative jurisdiction of the Zamboanga Peninsula region. The rest of Basilan's six municipalities were promptly inducted into the ARMM.
