Wahiawa is a census-designated place in Honolulu County, Hawaii, United States, on the island of Oahu. It is located in the Wahiawa District, on the plateau or "central valley" between the two volcanic mountains that comprise the island. In Hawaiian, wahi a wā means "place of noise", perhaps a reference to the fact that heavy surf on the North Shore could be heard from here, or to the sounds of the ancient military training exercises conducted on these plains. The population was 17,821 at the 2010 census.Lakes and reservoirs are rare in Hawaii, and Wahiawa is at once unique in being surrounded on three sides by Lake Wilson. The town must be accessed by either of two bridges on Kamehameha Highway across the narrow north and south arms of the reservoir. Outside of the reservoir, the town used to be surrounded by military bases and agricultural fields, but development is making its way up from the increasingly urbanized southern portion of the central plain.