Niwot is a census-designated place (CDP) in Boulder County, Colorado, United States. The population was 4,160 at the 2000 census. This locality is named for Arapaho Chief Niwot, a tribal leader in the Boulder area during the nineteenth century. The name means "left-handed." With a per capita income of $39,943, Niwot is ranked as the 17th wealthiest location in Colorado.