Coal Mine Ridge Trail and Arroyo Trail Loop

The Coal Mine Ridge Trail and Arroyo Trail Loop is a 8.0 km looped trail that starts and ends in Portola Valley, San Mateo County, California. Based on our data, the hike is graded as Medium. 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 2 hrs 4 mins. Caution is advised on trail times as this depends on multiple variables. For more info read about how we calculate hike time.