It formed as a result of the Honolulu Volcanic Series, which was a set of eruptions from the Koʻolau Range during its rejuvenation stage. The HVS also created other volcanoes such as Diamond Head. The eastern part of Ulupaʻu's rim was destroyed due to erosion. A cinder cone known as Puʻu Hawaiʻiloa is located nearby on the same peninsula.