Castner Glacier Ice Cave Trail

The feel

This is a popular walk up the braided Castner Creek valley to an ice cave carved by glacial meltwater beneath Castner Glacier. It is best known as a winter destination when the cave is stable. There is no maintained trail, but numerous social trails are easy to follow, and the route is flat with no noticeable gain in elevation.

In summer an unimproved road runs along the north side of the creek for about 1/2 mile, then a foot path continues another 1/2 mile toward the glacier. Extreme winds, fast changing water levels, active glaciers and rockfalls all make this a place with real hazards, and bears are frequently in the area.

What to expect

Route and terrain

Out and back, 2.6 miles total, with 50 ft of gain. Unmaintained and unmarked routes up Castner Creek, with the glacier a little over 1 mile from the road.

Time

About 1 hour out and back.

Crowds and best time

Popular as a winter destination.

Parking

Winter parking is usually available within the Richardson Highway right of way on the southwest side of the bridge, signed and maintained by Alaska DOT. After heavy snow, parking may not be available.

Fees and passes

No fee for individual recreational use.

Hazards

Ice caves are dangerous: meltwater can flow even in winter, glacier-locked lakes can drain without warning, and rockfall or cave collapse can occur. Bears are frequently in the area. Extreme winds and fast changing water levels.

Bathrooms and water

No toilets.

Season and access

Access is at milepost 217.3 on the Richardson Highway (AK-4) on the east side. Castner Creek blocks access to the cave until it freezes over, usually around mid-November. From roughly November through early May follow the packed trail on the south side of the bridge, and do not use the north trail from November through mid-May.

Mingo says

Aim for winter, once the creek has frozen over. Before then it is generally too deep to cross.

Before you go

• Plan for about a 2.5-hour drive south of Fairbanks to milepost 217.3 on the Richardson Highway.
• Expect no signs or guaranteed trails; numerous social trails are easy to follow.
• Treat the ice cave as dangerous, since rockfall or cave collapse can occur.

Written October 2026. Sources are listed at the end of this page.