History

Executive Order No. 103, dated May 17, 2002, divided Region IV (Southern Tagalog) into Region IV-A (CALABARZON) and Region IV-B (MIMAROPA).

President Gloria Macapagal-Arroyo issued Executive Order 103 (EO103) on May 17, 2002 which subdivided the Southern Tagalog provinces which were included in Region IV into two regions — Regions IV-A and IV-B — to promote efficiency in the government, accelerate social and economic development and improve public services. Region IV-A is now known as CALABARZON (which stands for the provinces of Cavite, LAguna,BAtangas, Rizal and QueZON). Region IV-B is known as MIMAROPA, standing for the island provinces belonging to the region — MIndoro (Oriental and Occidental), Marinduque, ROmblon and PAlawan. EO103 also transferred the province of Aurora to Region III in Central Luzon.

Executive Order 429 moved Palawan to Region VI on May 23, 2005.  After this, Region IV-B began to be called MIMARO instead of MIMAROPA. However, Palaweños criticized the move, citing a lack of consultation, with most residents in Puerto Princesa City and nearly all municipalities preferring to stay with Region IV-B. Consequently, Administrative Order No. 129 was issued on August 19, 2005 to address this backlash. This order directed the abeyance of Executive Order 429 pending the approval of an implementation plan for the orderly transfer of Palawan from MIMAROPA to Region VI.  The 2010 Philippine Census of Population continued to report the Region IV name as ‘Mimaropa’ and continued to list the province of Palawan as part of that region.  As of 2012, it is not clear whether or not the transfer of Palawan to region VI is still considered pending by the Philippine government. As of 2012, the National Statistical Coordinating Board of the Philippines continues to list Palawan province as part of the MIMAROPA region.