Kapaa, HI has a population of 10,753 and is the 3,740th largest city in the United States. The population density is 1,072 per sq mi which is 742% higher than the Hawaii average and 1083% higher than the national average. The median age in Kapaa is 42 which is approximately 8% higher than the Hawaii average of 39. In Kapaa, 60% of the population over 15 years of age are married, 86% speak English and 1% speak Spanish. 51% of Kapaa residents were born in Hawaii, 34% were born out of state, 3% were born outside of the United States and 12% were foreign born.