Guguan volcano is a 2.8 km wide island in the central Mariana Islands. The islands contains a caldera and a post caldera cone.
The island lies on the Mariana volcanic arc, 125 km above the Wadati-Benioff Zone.
The Guguan cross-chain extends due west from Guguan and trend perpendicular to the magmatic front. The history of volcanism in the Guguan cross-chain is poorly known. Guguan erupted in 1882–1884 but there are no records of any submarine eruptions.
At one time Guguan's volcano literally blew its top. The now dormant volcano rises up 988 hundred feet from sea level and then flattens out abruptly. After a good rain, there are waterfalls. A wildlife preserve, Guguan is home for thousands of white seabirds which roost in the cliffs.
There is a huge ancient lava flow on the barren west side, a striking gray comparison to the lush forests that cover the rest of the island. From Guguan you can see Alamagan in the distance.