Mandalagan is also known as Nahigda nga Babayi or Lying Women for the Bacolodnons and Negrenses.

Mandalagan is a deeply dissected complex volcano, with a highly altered volcanic dome.

One solfataric area emits a high-temperature (106 degrees C) plume to 30 m height with a roaring noise like a high-pressure geothermal borehole.

Rock type is principally andesitic with some dacitic A crater located near the center called "Tinagong Dagat", where hikers camp.

Philippine Institute of Volcanology and Seismology (PHIVOLCS) lists Mandalagan as potentially active.