Keaau, HI has a population of 2,672 and is the 9,426th largest city in the United States. The population density is 1,037 per sq mi which is 714% higher than the Hawaii average and 1045% higher than the national average. The median age in Keaau is 40 which is approximately 3% higher than the Hawaii average of 39. In Keaau, 49% of the population over 15 years of age are married, 74% speak English and 0% speak Spanish. 69% of Keaau residents were born in Hawaii, 10% were born out of state, 2% were born outside of the United States and 19% were foreign born.