To accelerate the social development of the provinces and cities comprising Region IV, Executive Order 103 dated May 17, 2002 divided the region into Region IV-A (CALABARZON) and Region IV-B (MIMAROPA).

Region IV-B or MIMAROPA (Mindoro Oriental & Occidental, Marinduque, Romblon, and Palawan) refers to the cluster of emerald islands and islets stretching across the warm tropical seas south of southern Luzon, composed of 2 cities, 71 municipalities and 1, 458 barangays. It is archipelagic having no land border with another region. It is bounded in the north by CALABARZON (Cavite, Laguna, Batangas, Rizal and Quezon) and Verde Island; in the southeast by Bicol region and Pacific Ocean; in the south lies Panay islands and on the west is South China Sea. MIMAROPA has a total land area of 2,745,720 hectares representing 9% of the country’s land. The 2010 Census revealed that MIMAROPA has a total population of 2,522,998.

The region’s economy relies mostly on agriculture, fishing and ecotourism. It is one of the producers of the country’s top export products like rice, banana, coconut, cashew, and papaya. The region is also the second top producer of fish and seaweed in the country. 

MIMAROPA is one of the busiest regions in terms of tourism.

Region IV-B is home to:

Mindoro Oriental – The Loveliest Harbor in the Island

Mindoro Occidental – The Marine Wonderland

Marinduque – The Lenten Capital

Romblon – The Marble Capital

Palawan – Home of the New Seven Wonders of Nature

Pursuant to Republic Act 10879 or MIMAROPA Act dated July 27, 2015, outhern Tagalog will be known as MIMAROPA Region.



Adopting the provision of EO No. 103, NIA created a separate regional office at MIMAROPA Region which was effected by virtue of NIA Board Resolution 7678-11 dated March 14, 2011 and Office Memorandum 26-2011 dated March 29, 2011 issued by Administrator Antonio S. Nangel. The regional office was established at Calapan City, Oriental Mindoro in accordance to Executive Order No. 682, designating Calapan City as the regional center of MIMAROPA Region.  

The MIMAROPA Regional Office is accessible by land-sea transport facilities. Calapan City is about 2 hours travel from Batangas Port via Roll-on/Roll-off ships and from Calapan Port, the office is 7 kms. travel via public/private vehicle.

NIA MIMAROPA Regional Office is headed by Acting Regional Manager Ronilio M. Cervantes together with Engineering and Operations  Division Manager Lowell L. Lozano and Administrative and Finance  Division Manager Kirsty Caroline M. Hernandez-Aceron. The Regional Office is composed of dynamic personnel joining hand in hand to achieve the agency’s goals.

NIA MIMAROPA covers 3 Irrigation Management Offices (IMO) headed by Division Managers: Engr. Gerardo R. Perez for MOMARO IMO (Mindoro Oriental-Marinduque-Romblon), Engr. Maria Victoria O. Malenab for Occidental Mindoro IMO and Engr. Fidel P. Martinez for Palawan IMO.