Douglas County, Colorado was named the third healthiest county in the nation by a recent U.S. News & World Report study. The report ranked the 500 healthiest counties in the United States, on factors including population health, education, economic strength and public safety. Castle Rock, the county seat and largest incorporated town in Douglas County, contributed to the high ranking with miles and miles of trails and acres of parks and open space. Only Los Alamos County, New Mexico and Falls Church, Virginia fared better.