Waipahu is a census-designated place (CDP) located in the ʻEwa District on the island of Oʻahu in the City & County of Honolulu, Hawaiʻi, United States. Historically, it served as a former sugarcane plantation town.
As of the 2020 census, Waipahu had a population of 43,485 residents. The area is identified by the U.S. postal code 96797.