The region was first created on August 1, 1989 through Republic Act No. 6734 otherwise known as the Organic Act. ARMM was officially inaugurated on November 6, 1990 in Cotabato City.
CotabatoCity is the regional center and the seat of the ARMMregional government, although the city itself is part of Region XII, an annex is also maintained in Zamboanga City, which is also not a part of it.
The AutonomousRegion in MuslimMindanao is composed of the 5 predominantly Muslimprovinces and Marawi City.