Lyons is a Statutory Town in Boulder County, Colorado, United States. The population was 1,585 at the 2000 census. Lyons is located at the confluence of the North St. Vrain Creek and the South St. Vrain Creek, twenty miles (32 km) east of Rocky Mountain National Park. Due to its location at the intersection of State Highway 7 and U.S. Highway 36 which lead to Rocky Mountain National Park, it is sometimes referred to as The Double Gateway to the Rockies.
Lyons is located at 40°13′26″N 105°16′8″W / 40.22389°N 105.26889°W / 40.22389; -105.26889 (40.223935, -105.269013).
According to the United States Census Bureau, the town has a total area of 1.2 square miles (3.2 km²), all of it land.