Lake Marie and Sugarloaf Peak Loop

HARD 15 reviews
#3 of 6 trails in

Lake Marie and Sugarloaf Peak Loop is a 7.6 mile moderately trafficked loop trail located near Napa, California that features a river and is only recommended for very experienced adventurers. The trail offers a number of activity options and is accessible year-round. Horses are also able to use this trail.

7.6 miles 2027 feet Loop



nature trips

trail running


horseback riding





wild flowers


no dogs

Skyline Wilderness Park is located in the hills immediately east of the town of Napa and rewards hikers with great terrain from oak forest and grassland to lakes and mountain tops. Winemakers know that Napa Valley is a great place to be all year round, hence it's possible to find great hiking conditions here on virtually any month of the year.

3 days ago

1 month ago

With all the recent rains there was a lot of running water, it was peaceful.

5 months ago

6 months ago

This was a decent, somewhat strenuous hike. It is *extremely* dusty. The first quarter of the trail is deceptively easy. Rock Rim was the hardest part of the trail by far.

7 months ago

Love it, I run it at least once a week. Its an excellent interval workout, with fantastic views, especially if you take Skyline to the top to loop around and Chapperell on the way out. Bring water! IMPORTANT: *Keep attention though*, the place is not joking about the Rattlesnakes, Wild pigs, Coyotes, and Mountain Lions that they warn you about on the many signs on the way to the trailhead. I run into at least one or 2 of those things every week. Making Noise on certain parts of the trail or going in a group is a good way to avoid problems, but makes it less likely to see wildlife. The Coyotes will run away, The mountain lions are very shy, My eye is always looking in the trail grass for rattlesnakes, and well; The wild pigs are *a**holes (but rarely encountered) Have fun!

8 months ago

9 months ago

awesome hike...very steep in areas...

very steep...start at skyline for xtra calories burned

9 months ago

10 months ago

10 months ago

10 months ago

I actually found this trail to be more of moderate type climb. The fact that it's switchbacks all the way up made it very easy to ascend.
There are areas where the trail is literally 12 inches wide and a mis step can send you into a ravine. All in all.... a beautiful walk.

11 months ago

1 year ago

1 year ago

I am giving the trail 4 stars on the assumption that, on a crisp and clear day, the views of Napa Valley and the North Bay must be quite beautiful. I did not get a chance to confirm that; I hiked the trail in mid-90s heat and widespread hazy conditions, courtesy of the forest fires to the North and West of Napa.

I had planned to hike Berryessa Peak Trail on that day but most trails in the vicinity of Berryessa lake were closed. I retreated to Napa and the Skyline Wilderness Park. Getting there later than I normally like to start a hike, I settled for an 8 miles loop.

Immediately after paying the day use fee ($5 as of 8/15/2015) at the gate, I turned right to snatch a spot in the parking lot that would be shaded in the afternoon (beats returning to a car that has turned into a toaster-oven). The access path to the trail system starts at the South West corner of the parking lot.

Below is a good description of how to get to the Skyline Trail from the parking lot. (Excerpt copied from the website). You may also just want to be on the lookout for "To Trails" signs.
" Begin on a trail starting at the edge of the parking lot, beneath a big coast live oak. A small RV park is off to the left, but the Martha Walker Native Habitat Garden creates a buffer between the trail and the campground. After passing some fruit and nut trees and climbing a few stairs, the trail seems to disappear in the middle of a picnic area. Stay to the right here (if you reach the Social Hall you're headed the wrong way), passing a row of elevated concrete stands.
On the far side of the picnic area, a wide trail swings in from the right, reaching a crossroads with a gravel road. Veer left onto signed Lake Marie Road. Coast live oaks, snowberry shrubs, and blackberry vines strain against a fence that closely borders both sides of the broad dirt road."
Once you reach the dirt road with chainlink fences on both sides, you are entering the trails system the loop uses.

I used the Skyline Trail (well marked in many different places) which is part of the Bay Area Ridge Trail circling the whole SF Bay. The Skyline trail is a bit of a roller coaster starting with a "healthy" climb to the ridge line via a series of switchbacks. After that, the trail mostly traces it course just below the ridge, on the East Side. At several points along the trail, sweeping views of the Napa Valley and the North Bay open up. The trail finally descends toward Lake Mary. The Skyline trail itself does not reach Lake Mary but instead hugs the hillside about 100 feet above the lake. If you want to get to the lake shore you will need to veer left as Skyline reaches the Northwest end (beginning) of the lake.

Past the lake, the Skyline trail crosses the creek (i splashed water on my t-shirt and shorts to cool down a little). You then have 3 options to got back:
(1) Retrace your steps on Skyline
(2) Take the Chaparral trail that follows the creek on the East side
(3) Continue .25 miles and take the Thatcher's Rim Rock Trail on the left.
I chose option 3, knowing in advance that the Rim Rock trail is advertised as "very steep and narrow". For once, advertisers did not lie! It is a sustained and at times very steep ascent from the creek to the summit of Sugarloaf Mountain. There is even a short series of tight small switchbacks that reminded me of "Walter's Wiggle" on the Angel's Landing trail of Zion National Park. Once on Sugarloaf Mountain, the good news is that it is pretty much all downhill from there.

At the point where Rim Rock gets down to the creek bed again there is apparently an option to rejoin the parking lot while staying on the East side of the creek. Not being sure that this was an option, I crossed the creek on a wooden bridge and turned right on Lake Marie road to return to the head of the Skyline trail (closing the loop) and, from there, to the parking lot. All said, a bit under 8 miles.