Wailuku is a census-designated place in and county seat of Maui Island, Maui County, Hawaii, United States. The population was 17,697 at the 2020 census. Wailuku is located just west of Kahului, at the mouth of the Iao Valley. In the early 20th century Wailuku was the main tourist destination on Maui, though it has since been eclipsed with the rise of the resort towns such as Kaanapali.