Kapaau is a census-designated place (CDP) in Hawaii County, Hawaii, United States, at the northern tip of the big island of Hawaii. The population was 1,159 at the 2000 census. It is celebrated as the birthplace of Kamehameha I.
Kapaʻau is located at 20°14′5″N 155°48′23″W / 20.23472°N 155.80639°W / 20.23472; -155.80639 (20.234711, -155.806361) in the North Kohala District of Hawaii County.
According to the United States Census Bureau, the CDP has a total area of 2.2 square miles (5.6 km²), all of it land.