Kaumakani is a census-designated place (CDP) in Kauaʻi County, Hawaiʻi, United States. The population was 749 at the 2010 census, up from 607 at the 2000 census.

Kauaʻi County, officially known as the County of Kauaʻi, is a county in the U.S. state of Hawaiʻi. It encompasses the islands of Kauaʻi, Niʻihau, Lehua, and Kaʻula. According to the 2020 Census, the population was 73,298. The county seat is Līhuʻe.