The Southwestern Tagalog Region, designated as MIMAROPA Region, is an administrative region in the Philippines. It was also formerly designated as Region IV-B until 2016. It is one of five regions in the country having no land border with another region. The name is an acronym combination of its constituent provinces: Mindoro (divided into Occidental Mindoro and Oriental Mindoro), Marinduque, Romblon and Palawan.
- Mindoro Oriental
- Mindoro Occicental