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1,939 ft
Distance
100 ft
Climb
-78 ft
Descent
00:05:30
Avg time
22 ft
Altitude change
523 ft
Altitude min
615 ft
Altitude max
594 ft
Altitude start
615 ft
Altitude end
1.115%
Grade
-18.271%
Grade max
41.064%
Grade min
518 ft
Distance climb
907 ft
Distance down
514 ft
Distance flat
00:05:30
Avg time
Under World Details
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Activities
- Mountain Bike
- Hike
- Trail Running
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Riding AreaJackson Demonstration State Forest
Mendocino, California -
Difficulty Rating
-
Local Popularity55 in Mountain Biking [+]
- 5 in Trail Running
- 55 in Hiking
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Global Ranking
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State Ranking
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Trail TypeSingletrack
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Bike TypeAM
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DirectionBoth DirectionsPopular In Reverse
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Climb DifficultyBlue
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Physical RatingModerate
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Dogs AllowedYes
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eBike Allowed
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Land OwnerJackson Demonstration State Forest
No community description for Under World trail has been added yet!
AI Generated Description
Under World is a 1,939 ft moderately popular blue difficulty singletrack trail located near Mendocino California. This mountain bike primary trail can be used both directions and has a moderate overall physical rating with a 100 ft blue climb. On average it takes 5 minutes to complete this trail.
Local Trail Association
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Please consider joining or donating to the local trail association to supportDonate to earn trail karma!
trail development & maintenance.
Traditionally Indigenous Territory
Recent Activity on Trail
Past Week
- 0 rides
6 Months
- 13 rides
- 14 miles avg distance
All
- 93 rides
- Last: Nov 14, 2025
Under World Trail Reports
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3D
Trail Conditions
- Unknown
- Snow Groomed
- Snow Packed
- Snow Covered
- Snow Cover Partial
- Freeze/thaw Cycle
- Icy
- Prevalent Mud
- Wet
- Variable
- Ideal
- Dry
- Very Dry
Trail Flow (Ridden Direction)
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The colour categories are based on what percentage of users are riding a trail in its intended direction.
The colour categories are based on what percentage of users are riding a trail in its intended direction.
- > 96%
- > 90%
- > 80%
- > 70%
- > 50%
- < 50%
- bi-directional trail
- no data
Trail Last Used
Trailforks scans activity logs to determine the last time a trail was ridden.
- < 2 days
- < 1 week
- < 2 weeks
- < 1 month
- < 6 months
- > 6 months
Trail Ridden Direction
The intended direction a trail should be ridden.
- Downhill Only
- Downhill Primary
- Both Directions
- Uphill Primary
- Uphill Only
- One Direction
Contribute Details
Colors indicate trail is missing specified detail.
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Trail Popularity ?
Trailforks scans activity logs to determine which trails are ridden the most in the last 9 months.
Trails are compared with nearby trails in the same city region with a possible 25 colour shades.
Think of this as a heatmap, more activities = more kinetic energy = warmer colors.
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- popular
- less popular
- not popular
ATV/ORV/OHV Filter
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Activity Recordings
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Activity Recordings
Trailforks uses anonymized public activity data.
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Winter Trails
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Missing Trails
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Least Popular
Trails are colored based on popularity. The more popular a trail is, the more red. Less popular trails trend towards green.
Jump Magnitude Heatmap
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BC Backroad Status
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Slope Aspect
Direction the slope faces
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Directions to under-world trailhead
(39.335310, -123.756378)
Photos
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Videos
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Routes with this trail
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Nearby Trails
- North Boundary Trail 75 ft
- Parallel Action 75 ft
- Condor 358 ft
- Rd 600 1,886 ft
- Lindquist Loops 2,224 ft
Jackson Demonstration State Forest
- By JackCoul & contributors
- #70743 - 988 views
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