High Ridge is a census-designated place (CDP) in Jefferson County, Missouri, United States. The population was 4,598 in the 2007 estimated census. It was 4,236 at the 2000 census. At 927 feet (283 m) above sea level, High Ridge is the second highest point in Missouri. It is also home to Olympic triathlete Sarah Haskins, who competed in the 2008 Olympics in Beijing, China.