Papaikou is a census-designated place (CDP) in Hawaii County, Hawaii, United States, and is a few miles north of the county seat, Hilo. The population of Papaikou was 1,314 at the 2010 census, down from 1,414 at the 2000 census.

Hawaii County is a county in the U.S. state of Hawaii in the Hawaiian Islands. It is coextensive with the Island of Hawaii, often called the "Big Island" to distinguish it from the state as a whole. The 2020 Census population was 200,629. The county seat is Hilo. There are no incorporated cities in Hawaii County. The Hilo Micropolitan Statistical Area includes all of Hawaii County. Hawaii County has a mayor–council form of government. In terms of geography, Hawaii County is the most expansive county in the state and the most southerly county in the United States.