Camarines Sur occupies the central section of the Bicol Peninsula. With a land area of 5,266.8 square kilometres (2,034 sq mi), it is the largest province in the Bicol Region. At the center of the province is the Bicol Plain, surrounded by mountains which include Mount Bernacci (Tangcong Vaca), Mount Isarog and Mount Iriga. The eastern portion of the province lies on the mountainous Caramoan Peninsula, which faces the island of Catanduanes to the east.
The Bicol River drains the central and southern parts of the province into the San Miguel Bay. Mount Asog is surrounded by three lakes: Buhi, Bato, and Baao.
