The Town of Lyons is a Statutory Town in Boulder County, Colorado, United States. The town population was 2033 at the 2010 United States Census, up from 1585 at the 2000 United States Census. Lyons is located at the confluence of North St. Vrain Creek and South St. Vrain Creek, 20 miles (32 km) east of Rocky Mountain National Park. Due to its location at the intersection of State Highway 7 and U.S.