Aniakchak National Monument and Preserve

Location/Size: On the Alaska Peninsula, 20 miles east of Port Heiden. Monument, 117,176 acres; preserve, 465,603 acres (97 percent federal).

Main Activities: Wilderness exploration, hiking, backpacking, kayaking.

Gateway Towns/Getting There: Port Heiden and King Salmon/scheduled air service from Anchorage. Monument access by floatplane to Surprise Lake, foot access through caldera, kayak access to Pacific via Aniakchak River.

Facilities, Camping, Lodging: No facilities. Primitive camping only.

Headquarters and Information: Headquarters, P.O. Box 7, King Salmon, AK 99613, 246-3305, www.nps.gov/ania.

Aniakchak Caldera is one of the planet’s finest examples of a dry cal-dera. Six miles in diameter, 2,000 feet deep, and covering about 10 square miles, its features include lava flows, cinder cones, and explosion pits. The larger caldera was formed thousands of years ago in a massive eruption that ejected an estimated 15 cubic miles of debris. Many smaller eruptions from vents and cones have followed, the last in 1931.

Surprise Lake on the eastern side of the caldera is the source of the Aniakchak River, a designated National Wild River that offers kayakers a spectacular trip to the sea on Class I–IV waters. The river cuts a 1,500-foot gash in the side of the caldera where it spills out to the southeast, heading for Aniakchak Bay and the Pacific. Floatplane shuttles to the lake are possible from King Salmon and Port Heiden (see the Appendix), both of which have regular air service from Anchorage.

Walking explorers can use the same shuttle services to reach the caldera and explore its wonders. There are no services or facilities—visitors must be self-reliant. Weather permitting, there are outstanding views of the Alaska Peninsula, Bristol Bay, and the Pacific from the caldera rim and the 4,400-foot summit of Vent Cone.