5.8 miles
1,060 ft
-1,063 ft
2 miles
High Point

This ride is one of the funnest stretches of creekside singletrack in Boulder County...followed by a heinous climb up to Miller Rock. From the trailhead you ride downhill following narrow, twisty singletrack - super flowy with the occasional tough technical move. And don't fall on those technical spots either as the steep drop to South St. Vrain Creek has claimed more than a few collarbones over the years.

At the bottom of the singletrack descent, take stock of your will power. The climb up to Miller Rock is a doozie, and don't forget you'll be climbing back out to the trailhead. Miller Rock is well worth it, though, with some of the best views of the Continental Divide around. Local lore has it that a man named Miller took refuge on the rock after a lynch mob came after him for stealing a horse (think about how bikers feel about bike thieves). Miller, being such a smart thief, snuck on top of the rock where he waited the lynch mob out...until he starved to death the tale goes.

There are two ways to get up to Miller Rock, and they are both heinous. We recommend the counterclockwise loop as the hair-raising descent is super fun in that direction. Bring a map as the roads and trails get confusing around here. First you'll ride, push, and carry your bike uphill on a nasty jeep road that has degraded into fields of babyheads in places. Once you flatten out bear left at the second intersection and continue up the jeep road to the base of Miller Rock.

For a nice view and a sweet snack spot, get off your bike, walk around to the backside of the rock, and scramble up. Once you've had your fill of the expansive views, get back on your bike and continue on until you see a trail to the left (continuing straight takes you to private property). This singletrack descent goes from fast and flowy to downright death-defying. Have fun, but remember how far from civilization you are at this point. The pucker factor weeds a lot of people off this trail after the first attempt. Once you are safely at the bottom again, it's time to ride back up the creekside singletrack to the trailhead.

Detailed Description
Ceran St Vrain/Miller Rock Loop is a 6 mile moderately popular expert route located near Ceran Saint Vrain Colorado. This mountain bike primary route can be used both directions and has a hard overall physical rating. This route includes 4 trails. This route climbs 1,060 ft with a max elevation of 8,624 ft then descends -1,063 ft.
Local Trail Association
Local trail association
Boulder Mountainbike Alliance (bouldermountainbike.org)
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Trail Products



  • Riding area
  • Primary Activity
    Mountain Bike
  • Other Activities
    • Hike
    • Trail Running
    • Horse
    • Snowshoe
    • Nordic Ski
  • Difficulty rating
    Black Diamond
  • Route Type
  • eBike Allowed
  • Bike type
    AM, XC
  • Direction
    Both Directions
  • Physical rating
  • Ridelogs
More Stats for Ceran St Vrain/Miller Rock Loop mountain bike route
  • Altitude min
    8,003 ft
  • Altitude start
    8,293 ft
  • Altitude end
    8,294 ft
  • Grade
  • Grade max
  • Grade min
  • Distance climb
    3 miles
  • Distance down
    3 miles
  • Distance flat
    3,632 ft
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Trail Conditions
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Recent Trail Reports Along Route

Ceran Saint Vrain Trail
Jan 5, 2022 @ 10:16am
Jan 5, 2022
Winter / fat bike conditions. Cleared some deadfall.
Miller Rock Spur Road Connector
Dec 12, 2020 @ 9:28am
Dec 12, 2020
A light covering of snow. Some patches of ice underneath.
Miller Rock Descent
Dec 12, 2020 @ 9:28am
Dec 12, 2020
A light covering of snow. Some patches of ice underneath.
more reports »
  • By WendyBMA BMA & contributors
  • #19939 - 1,056 views
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