MIMARO, also known as Region IV-B, is a region of the Philippines located in Luzon. The name is an acronym that stands for its provinces, which are: Occidental Mindoro, Oriental Mindoro, Marinduque, and Romblon. There is only one city in the entire region: Calapan City in Oriental Mindoro.
Executive Order No. 103, dated May 17, 2002, divided Region IV (Souhtern Tagalog) into MIMAROPA and Region IV-A (CALABARZON). Executive Order No. 429, dated May 23, 2005, transferred Palawan to Region VI
Administrative Order No. 129 was issued on August 19, 2005, to "resolve" the negative backlash and as part of the supervison of the transfer process of Palawan from MIMAROPA to Western Visayas.
| Province | Capital | Population (2000) | Area (km²) | Pop. density (per km²) | |
|---|---|---|---|---|---|
| Marinduque | Boac | 217,392 | 959.3 | 226.6 | |
| Occidental Mindoro | Mamburao | 380,250 | 5,879.9 | 64.7 | |
| Oriental Mindoro | Calapan City | 681,818 | 4,364.7 | 156.2 | |
| Romblon | Romblon | 264,357 | 1,355.9 | 195.0 | |