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Chalk Mountain Loop

  4.0 ( 2 ) Favorite


16.9 mile 27.3 kilometer loop
89% Runnable


Ascent: 2,767' 844 m
Descent: -2,767' -843 m
High: 1,569' 478 m
Low: 18' 5 m


Avg Grade: 6% (4°)
Max Grade: 54% (28°)


No Dogs
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Trail shared by Forthright

Good loop for training uphills and downhills.


Features River/Creek · Views


A loop in the Big Basin State park that prioritizes getting in vertical without being an out-and-back.

About 40/60 shade versus no shade, so bring plenty of water -- especially if you do it on a warm day.

Need to Know

Parts of this loop are shared with horses unfortunately.

Runner Notes

No trusted place to get water, except for the "start" at Horse Camp, since many trails near the streams also allow horses. If you plan on refilling water at a stream, bring a filter.


You definitely get some great views and since the aspect changes a lot, you get to experience both the drier foothill-like scrub to lush coastal redwood rainforest.

There are some sections that have enough steepness going down that you really do have to watch your speed and footing. But almost all of those sections don't have big drops or gnarly rocks and roots. There is enough grade (in steepness and length) that it can be worth bringing light poles to help you move faster uphill.

The first crossing of West Waddell Creek (if you're doing it clockwise) does not have a bridge, but is BEAUTIFUL. Depending on the time of year, it could be a mandatory to get your feet wet crossing. I did it on 7/12/2019 (18/19 was a big winter) and I was able to just barely make it across a shallow section dry with the help of poles. Maybe if you explored more upstream or down, or you were less allergic to poison oak, you could avoid this.

Great for a multisport day since the parking/start is in the same area as Waddell Creek Beach which is an awesome surfing and kiteboarding location depending on the part of the year.

Caltopo said my GPX file was roughly 16.5 miles, but it said 17.1 miles here when I submitted it, and now it's 16.9...

Flora & Fauna

POISON OAK! Especially on the first part of the trail that is the "Skyline to the Sea Trail Alternate" (even though a sign on the dirt road says to use it if you're a runner and not a car or horse).

Drier foothill-like scrub to lush coastal redwood rainforest.

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Aug 9, 2019
Gustavo Quepon
17.8 car to car starting from Waddell Beach parking lot. 17.8mi — 3h 50m
Jul 13, 2019
Ran out of water at mile 8. 17mi — 5h 00m

Trail Ratings

  4.0 from 2 votes


  4.0 from 2 votes
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in California


25 Views Last Month
162 Since Jul 13, 2019



The Skyline to the Sea Trail hosts a fantastic view of Waddell Beach.
Jan 26, 2017 near Brookdale, CA
West Waddell Creek Crossing explained looking upstream. I honestly had to stop and walk around to notice the downhill section due to the water level.
Jul 13, 2019 near Boulder…, CA
View of Año Nuevo from Chalk Mountain
Feb 16, 2019 near Boulder…, CA
Chalk Mountain view of Año Nuevo Island
Jul 13, 2019 near Boulder…, CA


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