Kapaau, HI has a population of 1,935 and is the 11,208th largest city in the United States. The population density is 673 per sq mi which is 428% higher than the Hawaii average and 642% higher than the national average. The median age in Kapaau is 41 which is approximately 7% higher than the Hawaii average of 39. In Kapaau, 51% of the population over 15 years of age are married, 78% speak English and 0% speak Spanish. 69% of Kapaau residents were born in Hawaii, 18% were born out of state, 1% were born outside of the United States and 12% were foreign born.