Waipahu is a former sugarcane plantation town and now census-designated place (CDP) located in the ʻEwa District on the island of Oʻahu in the City & County of Honolulu, Hawaiʻi, United States. As of the 2010 Census, the CDP population was 38,216. The U.S. postal code for Waipahu is 96797.
Waipahu is the name of an artesian spring. In Hawaiian, Waipahu is derived from wai, meaning water, and pahū, meaning "burst or explode"; combined, Waipahu means "water forced up (as out of a spring)". The early Native Hawaiians took pleasure in the cool and clear water gushing from the ground and named this spring Waipahu. Before the Western civilization set foot in Hawaii, the Hawaiians considered Waipahu to be the capital of Oahu. Royalty in the Kingdom of Hawaii would often gather and enjoy the fresh water from the spring Waipahu.
In 1897, Oahu Sugar Company was incorporated, and its board of directors located the sugar mill in Waipahu. It had 943 field workers. There were 44 Hawaiians, including 10 minors; 57 Portuguese; 443 Japanese, 408 of them contract laborers; and 399 Chinese, 374 of whom were contract laborers.