Tayabas Bay in the context of "Calabarzon"

Marinduque (/ˌmærənˈduːkeɪ/; Tagalog pronunciation: [maɾinˈduke]), officially the Province of Marinduque, is an island province in the Philippines located in Southwestern Tagalog Region or Mimaropa, formerly designated as Region IV-B. Its capital is the municipality of Boac, the most populous in the province. Marinduque lies between Tayabas Bay to the north and Sibuyan Sea to the south. It is west of the Bondoc Peninsula of Quezon province in mainland Luzon; east of Mindoro Island; and north of the island province of Romblon. Some parts of the Verde Island Passage, the center of the center of world's marine biodiversity and a protected marine area, are also within Marinduque's provincial waters.

The province of Marinduque was ranked number 1 by the Philippine National Police and Philippine Security Forces as the 2013 Most Peaceful Province of the country due to its low crime rate statistics alternately ranking with the province of Batanes yearly. Furthermore, for almost 200 years, the province has been home to one of the oldest religious festivals in the country, the Moriones celebrated annually every Holy Week.

Southern Tagalog (Filipino: Timog Katagalugan), designated as Region IV, was an administrative region in the Philippines that comprised the current regions of Calabarzon and Mimaropa, the province of Aurora in Central Luzon, and most of the National Capital Region. It was the largest region in the Philippines in terms of both land area and population. After its partition on May 17, 2002, Southern Tagalog continues to exist as a cultural-geographical region.

The region was and is still bordered by Manila Bay and the South China Sea to the west, Lamon Bay and the Bicol Region to the east, the Tayabas Bay, Sibuyan Sea, and Balabac Strait, where it shared a maritime border with Sabah, Malaysia, to the south, and Central Luzon to the north; it was bordered by Cagayan Valley to the north geographically.