Geology Hike: San Juan River Walk, Pagosa

Again this year, SJMA in conjunction with the US Forest Service, Pagosa and Bayfield Ranger Districts, is hosting educational geology hikes, free for the public, from May through October. These interpretive hikes, led and presented by geologists Dave Bouquet and Scott McAllister, will be in an area of the San Juan National Forest rich with evidence of earth’s geologic history from some of the area’s oldest metamorphic rocks, to Cretaceous seaways, to Tertiary volcanoes, to modern glacial deposits.

Pagosa Hot Springs, San Juan River Walk, Reservoir Hill, and the Story of the Mancos Shale

The world’s deepest geothermal hot spring is the Mother Spring aquifer located in Pagosa Springs, Colorado, USA. It is certified by the Guinness World Records, with a measured depth exceeding 1002 ft (305 meters), though it’s true, absolute bottom remains unknown.  When did it form and why is it there?  Your guide will explain it’s volcanic origin stemming for the largest ever volcanic eruption by volume in North America which created the San Juan Mountains.  We’ll walk along the beautiful San Jan River through downtown Pagosa Springs and then up onto Reservoir Hill where you’ll have an amazing view overlooking the town and of the San Juan Mountains and Pagosa Peak.  The guide will explain the origin of the black cliffs of the Mancos Shale which underlies the river’s course through the town.

Trail Information: This is a loop route, partially paved and partially rough trail.  Hike time is approximately 3 hours total, ~4.5 miles round trip, and about 350 ft. vertical ascent. We will walk along the river, then go over Reservoir Hill and make a loop through the downtown area.  There are multiple picnic areas nearby if you wish to bring your own lunch to eat after the hike or you can grab a bite at numerous nearby restaurants.

When: June 18, 2026 from 9:00am – 12:00 pm

Where: Group will meet at the Mary Fisher Park parking lot (on San Juan Street near the restrooms), downtown Pagosa Springs.

What to Bring:

• Layers of cool and warm clothing
• Water (1/2 to 1 liter per hour)
• Sturdy, supportive footwear
• Lunch/snacks
• Rain jacket or poncho
• Hiking Daypack
• Sunscreen and sunglasses
• Camera

Cost: Free, $10 donation is greatly appreciated!

Please Note: Although pets are allowed along the rout, we ask that pets be left at home as a courtesy to the other guests in the group.

Registration is required. Spaces limited to 25 attendees.