Glacier Ice Caving
Lava Tube Caving
Prince of Wales Island
Stereo Caving Photos
Alaska has various types of caves, including true limestone solution caves (found on Prince of Wales Island and in the Wrangell-St.Elias National Park), glacier caves (found in southern coastal mountains and in the Alaska Range), and even lava tubes (on the Pribilof Islands and on the Seward Peninsula).
There are many limestone caves on the northern end of Prince of Wales Island, including two mile long El Capitan Cave, to which the U.S. Forest Service has built a trail for easy public access. Nearby is El Capitan Pit, which at 586 feet was once briefly the deepest vertical shaft in the United States. More karst areas appear on numerous other nearby islands of the southeastern panhandle of Alaska, encouraged by the acidic muskeg of the temperate forests.
Other karst areas lie scattered across the interior of Alaska, from the Brooks Range (running across the state, north of the Arctic Circle) to the remote foothills of the Alaska Range (and Kuskokwim Mountains, southwestern Alaska). (Rather than give specific locations, I've grouped images from various interior cave regions together under the label "Mystery Mountains".)
Glacier caves are the easiest to access; several are located only an hour from Anchorage and contain over half a mile of surveyed passage in winter. Be cautioned that exploration of glacier caves is only safe after freeze-up and before snow accumulation to avoid melting and high avalanche danger.