Sourdough Trail is a 17.7 kilometer moderately trafficked out and back trail located near Boulder, Colorado that features a river and is rated as difficult. The trail offers a number of activity options and is best used from June until September. Dogs are also able to use this trail but must be kept on leash.

Distance: 17.7 km Elevation Gain: 491 m Route Type: Out & Back

dogs on leash

hiking

mountain biking

bird watching

running

forest

river

wild flowers

wildlife

bridge out

rocky

hiking
snow
4 days ago

Still a bit of snow on the trail. Most people were turning back after a couple miles. It’s a bit of a tougher hike with the snow, but very doable for experienced hikers.

hiking
snow
11 days ago

hiking
icy
snow
18 days ago

Great trail but lots of snow right now. I would recommend snow shoes for the last 5 miles.

hiking
1 month ago

Lot of new snow

hiking
snow
1 month ago

Hiked 4/6. Started mid afternoon because first and second hike choices we closed to non-county residents. Only went about 2 miles in (4 roundtrip) before turning back due to time constraints. Trail is still mostly hard/medium pack with a few melted tree wells. Used micro crampons to minimize slipping, but would have easily sufficed with just boots. Snow is starting to get soft and if there's another week of 60° days, snowshoes will probably be preferable. Saw some XC skiiers, they seemed to be getting by okay. Also, please pick up after your dogs, people! just because it's in the snow doesn't mean you don't have to pack it out!

snowshoeing
snow
4 months ago

Perfect conditions

hiking
snow
6 months ago

mountain biking
7 months ago

Nice trail. Plenty of coverage from sun. Enough climbing for a good workout without ever becoming grueling. Moderately technical terrain with a few tight switchbacks at south end.

hiking
7 months ago

Not great views but a good workout

hiking
rocky
8 months ago

An amazing hike. A bit rocky. Had to cross a stream. Went over a bridge the river was flowing good

hiking
8 months ago

uphill on the way back. only did half. very quiet and quite a few mountain bikers.

hiking
muddy
rocky
9 months ago

Trees.

hiking
9 months ago

Mostly shaded and not too many bugs, but not very rewarding views.

hiking
10 months ago

Had a great hike on 7/20. Challenging at parts but more of a steady climb with variations in the path.

hiking
11 months ago

Not bad for the first couple of miles. As you get over 10k feet the snow obscures and blocks the trail. Hard climbing up and over but went until the end. Best to wait another week or so.

hiking
bugs
11 months ago

Hiked 6/1. Most dry/no snow up until about the first 1.5 miles or so. From there parts of the trail are blocked with large mounds of snow. Most are okay to walk across but with the snow melting it can get unpleasant at times. Turned around after about a mile and a half. Beautiful area though and will plan to come back soon after the snow melts!

snowshoeing
snow
Mon Mar 18 2019

Trail is well marked and had a great day of shoeing.

hiking
Sun Jan 27 2019

Nice, peaceful hike through the woods. trail was covered in snow buy had no issues in hiking boots. very lightly trafficked. only say one other person and dog.

snowshoeing
Mon Nov 26 2018

Quiet wooded trail, but very windy.

hiking
Sun Aug 12 2018

Ended up here randomly after the line at Mitchel Lake was at least 30 deep and not moving to pay $10 to be crowded on that trail... This was the first trail parking lot on the road to Rainbow lakes so I stopped around 2pm. This is a heavily forested hike that snakes upwards through several different layers of trees. I made it just past the 3.9 mark on the map before i turned around at 5pm. This was not a "Hard" hike by any means unless they were speaking of the length of the trail itself. This was the 23rd hike i did this season and I found this to be more "moderate." There were very few actual views through the trees and there is a site with ruins of some sort up by the environmental testing site. Lots of wood piles and old rusted metal cans and glass. Minimal activity along trail. Secluded most of the hike. Again seeing people just leave their bags of dog crap right along side the trail multiple times. Does someone come and pick this s-it up because it didn't seem like it. Why do people leave trash on the trail? Leave no trace? Disrespectful. Don't bring a dog if you can't clean up after your mess. Was a good endurance hike. Would have gone further if i had started earlier. Gave it 3 stars because of the limited views and dog waste.

hiking
Sun Aug 05 2018

Drive ~ Not worth the far drive up unless you are going to camp and stay overnight. Drive is windy and nauseating... very slow going. Dirt road to get to trail is terrible! Must have AWD or 4x4 to traverse. Single lane only in most places = treacherous and dangerous. Trails ~ This was a moderate to hard hike. VERY rough and rocky. We went with kids and dogs and had a few stumbles and falls. Yikes. Trail markings not really clear between off-roaders/4x4 and hikers. We were nearly run over several times because we were on an incorrect pathway. No bathrooms or public use areas which I had read in another review there was some. The one area that looks like you can access is actually private property and says no trespassing. Regardless of these concerns, the scenery was nice and the pines smelled lovely. We did have a fine time, dogs had fun and being in the trees was cool - lots of cover and shade. Probably wouldn’t go again just because of the drive time and treacherous nature of the off-roads. Tags ~ kid-friendly, kids, dog-friendly, dogs, dogs on leash, hike, hiking, trees, nature

hiking
Sun Jun 17 2018

Gorgeous hike through the forest during a light drizzling rain. Saw less than a dozen hikers, bicyclists, and runners - not busy at all.

hiking
Mon May 28 2018

nice up and down. a few scenic views. some shade

hiking
Sat May 26 2018

Well marked trail. Not sure why this is rated difficult; it’s a good hike but the only challenging part was the amount of snow still here. Ended up here due to a road closure, no summit but a very secluded & quiet trail.

hiking
Sun May 13 2018

Went on 5/8. We were aiming for Rainbow Lakes but the road was closed so we opted for this trail instead. Much of the trail was still packed with thick snow. i didnt have snowshoes so a couple parts of it were a struggle, and I had to carry my little dog, lol, but it was a laughable and doable challenge. We only made it to the first creek then turned back. Trail is well marked which was much appreciated with all the snow cover. There were two sections that opened up so you get a nice view of the snow caped mountain across the way. Oh and there's a teepee!

hiking
Mon Apr 02 2018

Up until the bridge (even a mile or so after), was packed snow, no traction or snowshoes needed. After that, started to punch thru and didn't even make it halfway and lost the trail at one point due to snow drifting. Recommend snowshoes after bridge based on conditions today.

hiking
Tue Mar 27 2018

Currently mostly snow covered with a hard pack. No spikes or snowshoes needed!

snowshoeing
Wed Mar 07 2018

Super great! We got there early in the morning so there was plenty of snow. We saw a couple of people on the way but we mostly had the trail to ourselves. On the way down it had gotten quite packed down and there were lots of people.

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