East Portal & Adams Tunnel History Hike

Fri Sep 18 2026 at 09:00 am to 03:00 pm UTC-06:00

Estes Park Visitor Center | Estes Park

Rocky Mountain Conservancy Education Team
Publisher/HostRocky Mountain Conservancy Education Team
East Portal & Adams Tunnel History Hike
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Learn about the Colorado-Big Thompson Project, Alva B. Adams Tunnel, and visit East Portal on this guided history hike!
About this Event

Join the Rocky Mountain Conservancy for a hike exploring the history beneath Rocky Mountain National Park. This 5-mile round-trip hike from East Portal to Sprague Lake gains 750 feet in elevation and highlights the remarkable story of the Alva B. Adams Tunnel and the Colorado-Big Thompson Project.

Built during the New Deal era, the project diverted water from the Colorado River to the eastern plains—providing irrigation, hydroelectric power, and economic relief during a time of national hardship.

Along this moderate hike, we’ll discuss the ongoing balance between preservation and progress in the Park’s history. Our hike begins with a steep climb over a short distance, with occasional areas of loose ground, before leveling off for the remainder of this out and back route.

Who: Participants ages 16 and up.

Program Level: Challenging – These programs are ideal for people accustomed to hiking longer, steeper trails at elevations above 8,000 feet. Programs will include travel over rough, loose, and uneven terrain. Participants should be able to hike at a pace of 1.5 miles per hour while carrying their own food, water, and layered clothing.

This program is entirely field based.

When: Friday, September 18th from 9:00am to 3:00pm. Ending time is approximate and depends on traffic conditions and the pace of the group. Please leave yourself some free time after the hike in case we get back later than expected.

Where: We will meet at the Estes Park Visitor Center at 500 Big Thompson Ave, and travel together to the trailhead in Conservancy vehicles. Look for a large white van with Rocky Mountain Conservancy logos in the visitor center parking lot. Registration includes all park fees and permits.

What to Bring:

  • Bag lunch
  • Sun protection
  • Warm layers (weather depending)
  • Waterproof layer(s)
  • Water (2 liters recommended)
  • Sturdy trail shoes or hiking boots

Refund Policy:

Cancellations made more than 30 days prior to the start of the course are eligible for a full refund. Cancellations made fewer than 30 days in advance are not eligible for a refund.

Our programs proceed rain or shine, and participants should be prepared for inclement weather. However, should we decide to cancel a program due to unsafe weather or emergency conditions, we will notify participants by email and automatically issue full refunds.


Conservancy members get 10% off individual registration when you use the discount code in your membership email!

Not a member of the Conservancy? Learn more and join here:

If you have questions about this course, please contact the Field Institute by email at [email protected] or by phone at 970-586-3262.



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Event Venue & Nearby Stays

Estes Park Visitor Center, 500 Big Thompson Avenue, Estes Park, United States

Tickets

USD 85.31

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