The Department of Public Works and Highways was devolved to the Autonomous Region in Muslim Mindanao (ARMM) on October 12, 1990 by virtue of Executive Order No. 426, signed by then President Corazon C. Aquino, after the ratification of Republic Act 6734, otherwise known as the Organic Act for the Autonomous Region in Muslim Mindanao (ARMM) on August 1, 1989.
The Offices of the Department of Public Works and Highways (DPWH) within the Autonomous Region in Muslim Mindanao (ARMM) including their function, powers and responsibilities , personnel, equipment, properties, budgets and liabilities are placed under the control and supervision of the Autonomous Regional Government (ARG).
In particular, these offices are identified as the four (4) District Engineering Offices (DEO) in each of the four provinces and the Area Equipment Services (AES) located in Lanao del Sur, Maguindanao, Sulu and Tawi-Tawi.
The Autonomous Regional Government is responsible for highways, flood control and water resource development systems, and other public works within the ARMM
Republic Act 9054 otherwise known as an Act to strengthen and expand the Organic Act for the ARMM, amended RA 6734. The four (4) provinces of Lanao del Sur, Maguindanao, Sulu and Tawi-Tawi was expanded to include the Province of Basilan and the City of Marawi after the two (2) areas opted to join the expanded ARMM in a plebiscite conducted on August 14, 2001.