Poʻipū is a census-designated place located in the U.S. state of Hawaii. It is within Kauaʻi County along the island of Kauaʻi to the south. It has a total area of 2.8 square miles at 21°53′3″N 159°27′51″W. The elevation is 20 feet above sea level. As of the 2010 census data, it had a total population of 979. The population density was 437.9/sq mi.