The Sentinel – 9,945′ – Gallatin Range – MT


Hiking To The Sentinel In The Gallatin Range of Montana

Location: The Sentinel, Portal Creek, Gallatin Canyon, Gallatin Range
Trailhead: Upper Portal Creek Trailhead – 5.1 miles north of Big Sky Turn off, then 6.8 miles east on Portal Creek Road
Type: Out and Back
Time: 4 – 6 hours
Distance: 10.3 miles
Grade: I Class 1
Montana Peak Rank: #254
Upper Portal Creek Trailhead Elevation: 8060′
Windy Pass Cabin Elevation: 9100′
The Sentinel Elevation: 9945′
Elevation Gain/Loss: 2800′
Maps: USGS – The Sentinel, Hidden Lakes | Beartooth Publishing – Big Sky Area


The Sentinel sits at 9945′ along the crest of the Gallatin Range in SW Montana. Surrounded by wide open, high alpine meadows, The Sentinel offers breathtaking views in every direction. When starting from the Upper Portal Creek Trailhead in the Gallatin Canyon, the round trip hike consists of 10.3 miles and 2800′ vertical gain. This scenic walk in the mountains will take between 4 and 6 hours and is well worth the trip.

The Sentinel - Gallatin Range - MT
The Madison Range and Gallatin Canyon

There are many mountains called The Sentinel in the world. This hike to The Sentinel is located in the Gallatin Range of Montana near Big Sky, Windy Pass, and The Upper Portal Creek Trailhead. Start your adventure to The Sentinel on Portal Creek Road (FS 984), which is 5.1 miles north of Big Sky on Highway 191. Once you are heading East on the Portal Creek Road, take a right at the first fork. Continue on the very bumpy road until you see a sign at the next fork. Stay left at this fork and the road ends at the Upper Portal Creek Trailhead at 8060′. The road is extremely bumpy and good vehicle clearance is mandatory.

Portal Creek - Gallatin Range - MT
Portal Creek Turn Off When Heading South

At the trailhead, follow the trail on the east side or middle of the parking lot. If you head south you will end up going to Golden Trout Lakes. The correct trail is Trail 82 and heads toward Windy Pass. The signs warn that you are in bear country so be sure to bring bear spray and bells. The trail travels for 1.85 miles through the thick forests of the Gallatin Range. There are several small stream crossings. The first one is usually the largest of them all.

The Sentinel - Gallatin Range - MT
Upper Portal Creek Trailhead

The trail climbs steadily and eventually forks in an open meadow. If you continue east, you will end up at Windy Pass – a pass that lives up to its name. It was howling wind from all directions during the day that Mia and I did this hike.  I was very glad to have my Patagonia Simple Guide Hoody to keep the wind off.

If you head north on trail 420, you will come to the Windy Pass Forest Service Cabin in about 0.3 miles. When you pass a small stream, grab some water because there is no water for you or your dog from this point on. The Windy Pass Cabin must be reserved in advanced and can be book through the Forest Service for $30 per night. Learn more about the cabin on the Gallatin National Forest website or for more detailed information and easy booking go to

The Sentinel - Gallatin Range - MT
Windy Pass Cabin

The trail forks again at the cabin. Continue to the northeast (right) for another 0.7 miles until the trail intersects the Gallatin Crest Trail #96. From here it is only 2.3 miles to The Sentinel. Throughout this part of the journey, the trail meanders through wide open, mellow meadows and the views are outstanding – especially in the spring when the wildflowers are in bloom. Unfortunately, the trail is a bit narrow, which makes it hard to stay in the well-trodden path. Do your best to avoid causing erosion.

Gallatin Range
Looking South Toward Gallatin Range

Follow the trail along the ridge. There are large wooden posts that mark the trail in case you get lost. It’s easy to head to the first high point, but the trail actually works around this to the west. On the NW side of this first summit, a narrow and sometimes snowy trail crosses a steep, rocky face – a place where we saw abundant wolf prints in the slick snow. After crossing this section, the trail becomes wide and grassy again.

Gallatin Range and Paradise Valey
Mia with the Absorakas and Paradise Valley in Background
The Sentinel - Gallatin Range - MT
The False Summit with Lots of Wolf Prints

The trail works its way up and down over the rolling, grassy crest of the Gallatin Range. Eventually a small stick propped up by a few rocks signals that you are at the top of The Sentinel at 9945′. The Sentinel is the highest point on the USGS Sentinel quad topo map. From the south, it is easily approached by the wide, grassy ridge, but to the west, north, and east, it drops off steeply.

The Sentinel - Gallatin Range - MT
The Final Approach To The Grassy Top of The Sentinel

The actual summit of The Sentinel is anti-climatic, but it’s a great place to sit down and enjoy the scenery of SW Montana. Expansive drainages drop down into both the Gallatin Canyon and the Paradise Valley. Breathtaking views of the Absorakas, Madisons, Gallatins, and beyond can be seen in every direction. The view of Portal Creek offers up views of the FS road you approached from. Big Sky Resort stands out in the distance. Other peaks like Emigrant, Ramshorn, Gallatin, Beehive, Lone Peak, Sphinx, and Eaglehead dominate the skyline. It’s easy to spot the headwalls above Hidden Lakes and Golden Trout Lakes – two other amazing hikes in the Portal Creek area. All and all it is one of the more impressive views from the Gallatin Range that I have seen.

The Sentinel - Gallatin Range - MT
River and I at Summit.
Lone Peak
Lone Peak and Big Sky
The Sentinel - Gallatin Range - MT
Looking NE toward Paradise Valley
The Sentinel - Gallatin Range - MT
The Taylor Hilgards
The Sentinel - Gallatin Range - MT
The Madison Range and Gallatin Canyon

After you soak in the views, head back the same way you came. It’s an out and back trail, which means when you stand on the summit, you are only half way home. Overall this hike took about 4.75 hours and Mia, River, and I covered 10.3 miles. We didn’t see any wildlife except a few wolf prints and plenty of horse manure. It was an absolutely awesome time.

The Sentinel - Gallatin Range - MT
Looking South – Trail follows right ridge
The Sentinel - Gallatin Range - MT
Looking South Back Down Trail

Hiking to the 9,945′ summit of The Sentinel in the Gallatin Range is an incredible way to spend a day in late October. While the summit of The Sentinel lacks the excitement of standing on a dominant peak, the mellow meadows of the Gallatin Range offer views that can’t be experienced anywhere else. This is definitely a hike to put on your to-do list.

The Sentinel - Gallatin Range - MT
Trail via Gaia GPS

Here are additional photos of the hike to The Sentinel in the Gallatin Range:


The Sentinel hike was completed on October 25, 2014.