Isarog is an active[6] stratovolcano located in the province of Camarines Sur, Philippines, on the island of Luzon.

[9] The broad isthmus between Lagonoy Gulf and San Miguel Bay is occupied by the isolated Isarog volcano.

A major debris avalanche deposit extends northwest to the coast and into San Miguel Bay.

Isarog Volcano was where local troops of the Philippine Army and Constabulary units and Bicolano guerrillas hid during the Japanese Occupation.

In the 1970s, with the leadership of Romulo Jallores and his brother, they established the New People's Army in the Bicol region at the foot of this mountain.

[11] Isarog Volcano is interpreted to have formed during the Pleistocene, as indicated by K-Ar dating of lava samples from the edifice, which yielded an age of 0.16 ± 0.12 Ma.

[13] Block-and-ash flows originating from lava dome collapses have occurred during the Holocene, one of which has a calibrated radiocarbon date of about 3,500 BCE.

In 2020, a group of geologists from Partido State University discovered that Isarog also erupted around 4,300 years ago after a charcoal overlain by thick block-and-ash flow deposits was found.

This new information about the eruptive history of Isarog was presented at the 2020 Virtual GeoCon, a convention of geologists organized by the Geological Society of the Philippines.

They belong to the Aeta people classification, but have distinct language and belief systems unique to their own culture and heritage.

The grassland (parang) is dominated by cogon (Imperata cylindrica) and talahib (Saccharum ovatum) grasses.

The topography and soil condition of the area limits the growth of trees, giving rise to the grassland.

Although it has no direct economic value, its presence in Isarog Volcano is a barometer of wealth and management of its natural resources.