Name: Coal Seam
Rating: 3.7

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Plan in onX Backcountry

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Dogs Leashed

E-Bikes Allowed

E-bikes allowed per regulation: bouldercolorado.gov/guide/g…

Description

A fun connector with an extremely rocky option, and a very easy walking path option. The trail heads south, paralleling 93, and works its way up to a connection with Community Ditch.

Contacts

Local Club: Boulder Mountainbike Alliance

Nov 17, 2025: Trail Update: South St Vrain

Nov 14, 2025: Another Step Closer to new Betasso Connector

Oct 24, 2025: Boulder County Moves One Step Closer to a Safer Boulder-to-Betasso Connection

Land Manager: City of Boulder, Colorado - Parks and Recreation

Shared By:

Garrett Lodewyck with improvements by Austin Cowan

Full Details

Trail Ratings

3.7 from 14 votes

#2

in Marshall Mesa

#12004

Overall

3.7 from 14 votes

5 Star		7%
4 Star		57%
3 Star		36%
2 Star		0%
1 Star		0%

Trail Rankings

#2

in Marshall Mesa

#1,157

in Colorado

#12,004

Overall

2 Views Last Month

916 Since May 1, 2013

		7%
		14%
		71%
		7%
		0%
		0%

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Photos

Heading out from the trailhead, the smooth wide trail awaits - much like most of the DIrty Bismarck surface.

Mar 26, 2013 near Superior, CO

1 Comment

Weather

Current Trail Conditions

All Clear 28 days ago

Update Conditions See History

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Check-Ins

Sep 20, 2024

Patrick Burns

If only this was downhill only and 3 miles long. Natural fucking awesome loose corners. A brief sample of perfect prairie MTB.

May 3, 2022

Loren D

Marshall Mesa trailhead open again!

Apr 3, 2022

Private User

Jul 12, 2020

Becky Lynn

May 14, 2019

Agustin Aguilera

Aug 14, 2018

William Horst

May 26, 2018

Cari Schnepp

Nov 13, 2016

Paige Schavey

Nov 1, 2016

Ryan Gross

Oct 31, 2016

Ryan Gross

Sep 19, 2016

Ryan Gross

Jul 10, 2016

Pat Grewe

Jun 28, 2016

Pat Grewe

Sep 17, 2015

Pat Grewe

Aug 9, 2015

Paul Billings

Jun 9, 2015

Jared Crockett

Fun little trail

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Beautiful evening light and views of the Flatirons and Continental Divide from the Marshall Mesa trail in South Boulder.

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Coal Seam

“Super fun connector trail at Marshall Mesa trailhead. ”

0.6

0.9

5,718' 1,743 m

5,567' 1,697 m

151' 46 m

0' 0 m

5%

9%

Toolbox

Know This Trail?

Dogs Leashed

E-Bikes Allowed

Description

Contacts

Shared By:

Trail Ratings

#2

#12004

#2

#1,157

#12,004

Photos

1 Comment

Comment Type:

Weather

Current Trail Conditions

Check-Ins

Nearby Recommended Routes

Dirty Bismark

Marshall Mathers LP

Rock Creek Farm Loop

East Boulder Trail

White Ranch: Technical Descent Tour

Lauren's Loop

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