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Dirty Bismark

RECOMMENDED ROUTE
Intermediate Intermediate
 3.5 (280)
  1. Areas
  2. CO
  3. …Front Range
  4. …Boulder
  5. Marshall Mesa
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“A fun Boulder area cruise following the famous Morgul Bismarck road course. ”

Michael Ahnemann
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Map Key

15.7

Miles

25.2

KM

90%

Singletrack

5,953' 1,814 m

High

5,524' 1,684 m

Low

933' 284 m

Up

929' 283 m

Down

2%

Avg Grade (1°)

15%

Max Grade (9°)

Dogs Leashed

E-Bikes Allowed

Overview

This ride follows the well-known Morgul Bismarck road cycling route - a famous race stage in the 70's and 80's.

The trails are easily accessible from Boulder, Superior, and neighboring towns, and it's mostly smooth with just a few slightly technical spots. It's just challenging enough to keep advanced riders interested, but rideable by just about everyone. This makes it a popular route, and it's often rideable almost all year.

Need to Know

There are several trailheads along this route, so start wherever it's convenient. You can also cross over Route 93 in a couple of places to ride more of the Marshall Mesa trail system. A great spot to do this is at the Greenbelt Plateau parking area to add on the west half of the Spring Brook Loop for an additional 8.3 miles and more singletrack.

Description

The trail as marked here starts and ends at the Marshall Mesa trailhead, which is the largest trailhead along the trail, closest to Boulder. From the trailhead, you'll head onto the Marshall Valley Trail, which is mostly flat with a short solid-rock playground thrown in.

The trail soon crosses a bridge and meets up with Cowdrey Draw and Community Ditch trails. Take a left onto Cowdrey Draw and you'll head mostly downhill on singletrack, popping out at 66th Street.

Continue through the gate and across the road and you'll now be on the Mayhoffer-Singletree extension trail, heading towards Superior. This section twists back and forth on itself and climbs just a bit. It's a serene, rural part of the ride - you're likely to see horses or cows along the way, and it feels like you're farther away from the neighboring roads than you are.

Next you'll meet up with the Meadowlark Trail, which climbs a bit, right next to an office building. The rural feel will go away for a bit until you head away from the office building and back towards a reservoir. Then the trail heads south next to McCaslin Blvd. until you reach the Coalton Trailhead.

This section of trail (Coalton Trail) l is mostly dirt road, and it gets you to the top of Marshall Mesa. Keep going until you reach yet another small trailhead to meet up with the High Plains trail.

Follow the High Plains trail, which is singletrack with a few mildly technical rocky sections. You'll eventually reach the Greenbelt Plateau trailhead where you can either cross Route 93 to meet up with the rest of the Marshall Mesa trails, or continue along this ride back towards the start.

Continuing along this ride, you'll end up on the High Plains Trail, which is singletrack, with a few mildly technical rocky sections. From here, turn right onto Greenbelt Plateau Trail and climb this mellow, mostly smooth section of trail. After the trail starts back downhill, take a right turn over a couple of log stairs, then down a bit more to some more log stairs and a short technical rocky bit, and over a bridge to cross the irrigation ditch.

Turn left onto the Community Ditch trail heading west, and ride until you reach Route 93. Here, you have another option to cross 93 and ride the Marshall Mesa trails to the west. But to get back to the trailhead, take a right onto Coal Seam.

Coal Seam is mostly downhill back to the trailhead, and somewhat technical, with twists and turns and rocks to keep things interesting. Ride the final rock garden, or ride around it, and you'll be back where you started.

History & Background

The Morgul Bismarck is a relatively famous stage from the Red Zinger / Coors Classic road cycling race from the 1970's and 1980's. Over time, trails along the perimeter of this classic road route have been built, making the Dirty Bismarck MTB trail.

Contacts

Local Club: Boulder Mountainbike Alliance

Feb 22, 2024: Join us in Shaping Colorado’s Outdoor Future

Feb 1, 2024: Eagle-Sage Trail Closures

Jan 31, 2024: Coalton Trail Reopening Feb. 1

Land Manager: Boulder County, CO - Parks and Open Space

Shared By:

Michael Ahnemann with improvements by JSON F and 3 others
Full Details

Trail Ratings

  3.5 from 280 votes

#2

in Marshall Mesa

#225

Overall
  3.5 from 280 votes
5 Star
17%
4 Star
35%
3 Star
35%
2 Star
11%
1 Star
2%
Recommended Route Rankings

#2

in Marshall Mesa

#73

in Colorado

#225

Overall
264 Views Last Month
58,327 Since Mar 21, 2013
Intermediate Intermediate
17%
13%
67%
1%
1%
0%
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Photos

Beautiful evening light and views of the Flatirons and Continental Divide from the Marshall Mesa trail in South Boulder.
Nov 11, 2016 near Superior, CO
Dirty Bismarck heading towards the main parking lot.
Oct 18, 2015 near Superior, CO
South end of the route, looking west.
Jun 10, 2024 near Superior, CO
Small technical section on an otherwise fast trail. Beautiful views of the front range from the Dirty Bismarck.
Oct 30, 2015 near Superior, CO
Looking out to the Flatirons from the Greenbelt Plateau.
Mar 26, 2013 near Superior, CO
Front Range fun on Dirty Bismark
May 22, 2018 near Superior, CO

18 Comments

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Current Trail Conditions

All Clear 37 days ago
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Check-Ins

Oct 13, 2024
Patrick Burns
Too much road but still a great XC style loop. Made for pushing. None of the riding is special so you focus on trying to go fast. Also scenic.
Sep 5, 2024
Jake Albright
w/ Kelsey
Aug 27, 2024
Raputa Thebeauta
11mi
Jul 27, 2024
Christopher Scott
Great early morning ride, inclines were most challenging part-not steep but steady.
Jun 19, 2024
Uriah Nevins
gravel bike, clockwise only 15mi — 2h 05m
Jun 10, 2024
Todd Williams
May 27, 2024
Rob Jenkins
Apr 15, 2024
Elizabeth Sexton
17.6mi

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