Coal Seam Trail, Marshall Valley Trail and Spring Brook Loop South Trail

The Coal Seam Trail, Marshall Valley Trail and Spring Brook Loop South Trail is a 18.4 km looped trail that starts and ends in Eldorado Springs, Boulder County, Colorado. Based on our data, the hike is graded as Easy. For information on how we grade trails, please read measuring the difficulty of a hiking trail on hiiker. Also, check our latest community posts for trail updates. This hike can be completed in approx 4 hrs 10 mins. Caution is advised on trail times as this depends on multiple variables. For more info read about how we calculate hike time.