Autonomous Region in Muslim Mindanao From Wikipedia, the free encyclopedia Island group Mindanao Regional center Cotabato City Government • Governor Mujiv Hataman (OIC) Area • Total 26,974 km 2 (10,415 sq mi) Population (2010) • Total 3,256,140 • Density 120/km 2 (310/sq mi) Time zone PST (UTC+8 ) Provinces 5 Cities 2 Municipalities 113 Barangays 2,470 Cong. districts 8 Languages Banguingui , Maguindanao , Maranao , Tausug , Yakan , Sama , others Province Capital Population (2010) [4] Area (km²) Pop. density (per km²) Basilan a Isabela City b 293,222 1,994.1 147.0 Lanao del Sur Marawi 933,260 12,051.9 77.4 Maguindanao c Buluan 944,718 7,142.0 132.2 Sulu Jolo 719,290 2,135.3 336.4 Tawi-Tawi Bongao 366,550 3,426.6 107.0 The Autonomous Region in Muslim Mindanao (abbreviated ARMM) is the region , located in the Mindanao island group of the Philippines , that is composed of predominantly Muslim provinces , namely: Basilan (except Isabela City ), Lanao del Sur , Maguindanao , Sulu and Tawi-Tawi . It is the only region that has its own government. The regional capital is at Cotabato City , although this city is outside of its jurisdicon. The ARMM previously included the province of Shariff Kabunsuan unl 16 July 2008, when Shariff Kabunsuan ceased to exist as a province aſter the Filipino Supreme Court declared the "Muslim Mindanao Autonomy Act 201", which created it, unconstuonal in Sema v. Comelec . [1] On 7 October 2012, President Benigno Aquino III said that the government aimed to have peace in the region and it will be known as "Bangsamoro ". [ Geography The ARMM spans two geographical areas: Lanao del Sur and Maguindanao (except Cotabato City) in south western Mindanao , and the island provinces of Basilan (except Isabela City), Sulu and Tawi-Tawi in the Sulu Archipelago . The region covers a total of 12,288 km².