High Quality Content by WIKIPEDIA articles! Agrihan (also spelled Agrigan) is a stratovolcano which forms an island in the Northern Mariana Islands in the Pacific Ocean. The entire island is a massive volcano which rises over 4,000 meters (13,120 ft) from the ocean floor, and is the fifth largest in the Marianas volcanic arc. At 965 m (3,166 ft), its summit is the highest point in Micronesia. The volcano is topped by a large caldera, 1 x 2 km (0.6 x 1.2 mi) in size and about 500 m (1,640 ft) deep.