Castner Glacier Hiking Guide

Visiting the glacier cave at the terminus has become incredibly popular in the last few years. Always exercise extreme caution when entering, as rock and ice can frequently fall from the ceiling, especially at the entrances, and can be extremely dangerous in the summer.

Alaska Guide | Interior Hiking

Popular ForGlacier cave, Hiking, Backpacking, Skiing, Snowshoeing, Mountaineering
DifficultyEasy to Very Difficult
Distance2 miles round-trip (glacier toe). As far as you want or are capable beyond.
Map route distance: 18.1 miles round-trip
ElevationNegligible to the glacier toe
Map route: 3370 ft (1027 m)
Backcountry SkillsEasy to walk or snowshoe up to the toe of the glacier (location of glacier cave)
Beyond extensive skills needed, especially in winter – avalanche preparedness, crevasse rescue skills, traveling in bear country, glacier travel, navigation
LocationMile 217.3 Richardson highway (Castner Creek)

The guidebook Delta Range: A Mountaineering Playground by Stan Justice is available in Fairbanks at Beaver Sports. It highlights many of the climbable peaks accessible by the Castner Glacier.

Blue: winter “trail” to the Castner Glacier toe and glacier cave – Red: route from 2015 trip to Thayer Hut


The Castner Glacier is an easily accessible glacier in the Delta Mountains of the Alaska Range. Popularized by the guidebook Outside in the Interior and many recent social media posts of the ice caves, the route to the Castner Glacier has become a well-traveled trail in winter. Because of this, I remind you to always follow Leave No Trace principles when in the backcountry and pack out whatever you bring in.

Castner Glacier – Hiking Guide
An ice cave near the southern margin of the glacier at the toe

Beyond the glacier toe, the first 6-7 miles of the glacier are debris-covered and partially vegetated. It’s one of the few glaciers I’ve had to bushwack on for a short stretch. This east-west running glacier splits at about mile-7 from the road into a north (main branch or White Princess Branch) and south (M’ladies branch). About a mile up the northern branch is the Thayer Hut, an alpine hut installed and maintained by the Alaska Alpine Club.

The Castner Glacier route can be used to access the peaks Silvertip, Triangle, Rum Doodle, Mary’s Rock, White Princess, Black Cap, and many others. Refer to Stan Justice’s Delta Range: A Mountaineering Playground for more details.

Driving Directions to Castner Creek and The Castner Glacier

The Castner Glacier is about a 2.5-hour drive (one-way) south of Fairbanks, Alaska. The route to access the Castner Glacier begins at Castner Creek along the Richardson Highway, south of Delta Junction (mile 217.3). There is parking on either side of the bridge at Castner Creek on the Richardson Highway, however, it is preferable and safer to park in a large pull-off about 0.1 miles south of the bridge. It’s a very short walk to the trailhead from here, but a much safer place to pull in and out.

Castner Glacier Area Weather Forecast

The Hike

Castner Creek Approach

The route follows Castner Creek upstream (east) from the road. There is no maintained trail to access the glacier. However, there is enough foot traffic that there are numerous easy-to-follow social trails to get access to the glacier toe. In winter and spring, there is often a packed snowshoe trail on the south side of the creek that is easy to follow to the ice caves and glacier toe. If there isn’t a visible trail, stay on the south side of the creek until you reach the terminus. It’s a little over 1 mile to the glacier.

In summer, you can access it from either side of the creek, but to gain access to the current cave entrance, you’ll want to stay on the north side. The easier south side follows a short ATV trail before dropping onto the riverbed. From here, you will mainly follow the riverbed with some occasional bushwacking in the willows, following the creek up to the toe. Alternately, a road on the north side of the bridge leads to a few good roadside camping locations and another spot to start the hike (refer to map). Follow the north side of the riverbed to the toe. If continuing on the glacier, you will need to cross the moraine to the highest southern moraine.

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It’s at the toe that you can frequently find ice caves. There used to be a system on the southern margin, but in recent years has been collapsing and receding quite fast there. The moraine is getting nasty, and it’s so close to the valley wall that it’s a terrible terrain trap for avalanches. In the last few years, there has been a great Röthlisberger channel (R-channel – semi-circular channel at the glacier base) almost in the middle of the toe.

Entrance to the glacier cave

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The Moraine

Looking down the large medial moraine on the Castner Glacier in the Alaska Range
Looking down the largest moraine and the best path up the glacier

The easiest way up to either ice tongue is to walk, ski, or snowshoe on the southernmost medial moraine. The moraine is straightforward to find as it is the highest point on the glacier and is a relatively smooth ridge all the way to the junction. In summer, beware of soft spots. You can easily find yourself knee-deep in mud that looked like solid ground.

The scenery to the south is fairly impressive. There are numerous large hanging glaciers and big peaks. The view is even nicer when you hit the junction. There are large icefalls to see up the White Princess Branch. Also up the White Princess Branch is a stunning view of Silvertip.

It might be tricky finding a way down onto the ice in summer. There is a sizeable canyon where the moraine meets the ice surface. Spend a minute looking for the best route from above. Remember this spot by landmark or mark it on a GPS for the return trip. Beware that later in the day the stream may be much more full.

White Princess Branch of the Castner Glacier in the Alaska Range
White Princess Branch

Thayer Hut

N 63° 27.156’ W 145° 32.181’ – 4800 ft (1463 m)

The Thayer Hut sits on a shelf above the glacier on the north side of the Silver Tip branch where it joins the main trunk of the glacier. You must be a member of the Alaska Alpine Club to use the hut. In winter you will want to be roped up and be knowledgeable in crevasses rescue as there are numerous crevasses in this area. The slope leading up to the hut poses avalanche risk as well. In summer you can cross the moraine in a semi-crevasse-free zone a few hundred feet to the northeast of the hut. You’ll traverse the more gentle talus slope above the red and tan cliffs to the point.

Surface Stream on the Castner Glacier near the Silvertip branch
Surface Stream near the Silvertip branch

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Ice caves are dangerous. They were formed by meltwater under the glacier and can have water flowing even in winter. This water is often very turbulent, fast, and very powerful. Additionally, events called jökulhlaups can occur where glacier-locked lakes drain catastrophically and completely fill these tunnels with no warning from below. Other hazards include frequent rockfall from the moraine above or total cave collapse. In winter these dangers are not as prevalent but still exist. Exercise extreme caution if entering.

Bears are frequently in the area. Know how to stay safe, avoid encounters, and properly protect yourself in the event of an encounter.

There is no official or maintained trail. Be familiar with navigation and have a compass, map, and/or GPS handy. On the glacier whiteouts are common. It’s nearly impossible to tell the direction in those conditions. The glacier is fairly crevassed and avalanche or rockslide risk on the slopes is high (even small slopes like the moraine). Know your skill level and your limits before attempting any backcountry travel!

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The O'Brien Icefall from the Castner Glacier
Looking at the O’Brien Icefall on the White Princess Branch
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