Wailuku, HI has a population of 16,179 and is the 2,648th largest city in the United States. The population density is 3,073 per sq mi which is 2312% higher than the Hawaii average and 3292% higher than the national average. The median age in Wailuku is 41 which is approximately 6% higher than the Hawaii average of 39. In Wailuku, 57% of the population over 15 years of age are married, 78% speak English and 3% speak Spanish. 61% of Wailuku residents were born in Hawaii, 23% were born out of state, 2% were born outside of the United States and 13% were foreign born.