Aniakchak National Monument and Preserve in Alaska is the least-visited unit of the National Park System/NPS

Need to get away from it all? Head to Aniakchak National Monument and Preserve in southwestern Alaska. Just don't forget your bear spray.

Year after year, Aniakchak rings in as the least-visited unit of the National Park System. Over the past decade, the monument has averaged just 71 visitors a year. Last year was something of a banner year, with 100 visitors tallied by the National Park Service. That's a far cry from the 30.3 million who visited the Blue Ridge Parkway last year.

Why is Aniakchak's visitation so low? Because you really have to work to get there, and once you do, you have to fend for yourself.

Aniakchak, comprised of the 127,176-acre national monument and the adjacent 464,118-acre national preserve, is a primitive volcanic landscape with no federally-maintained public facilities. The defining aspect of this landscape is a 6-mile wide, 2,500-foot deep caldera that was formed during a massive volcanic eruption 3,500 years ago.

Surprise Lake, seen from the rim of the caldera/NPS

The National Park Service imposes no operating hours or seasonal restrictions at Aniakchak. Access to and movement within Aniakchak, however, may be limited at any time depending upon prevailing weather conditions and/or volcanic activity, the agency notes.

And then there are the bears.

"Brown bears remain numerous throughout Aniakchak because of good forage conditions and seasonal availability of ample dietary protein in the form of salmon," the park's website notes. "Remember: Bears come here to fish, too. When bear activity is at its peak, both bears and anglers compete for the same resources. Stop fishing whenever bears are close enough to see or hear you and break your line if you encounter a bear. A bear quickly learns to associate anglers and/or the splashing of a fish in play with an easy meal and can take away your fish in seconds."

And the weather.

"Summer temperatures in this part of Alaska average in the high 40s to low 50s degrees Fahrenheit, with most days overcast and wet," notes the Park Service. "Coastal areas are often shrouded in fog and rain. Winds are frequent and even in summer these conditions can lead to hypothermia, the dangerous lowering of the body's core temperature."

And the remoteness.

"You're on your own. This is the No. 1 message preserve visitors must know and apply to their visit to Aniakchak," the Park Service warns. "There is no cell phone service and there are no amenities, services, or other infrastructure in the monument or preserve. When you depart you may not see another person until your return to civilization or your pilot comes to pick you up. Visitors must be self-reliant and able to execute self-extraction and communication, should an emergency situation arise."

So why head to Aniakchak? The challenging landscape includes the Aniakchak River, which was designated a national wild river in 1980.

Its spectacular resources make rafting the Aniakchak a most rewarding experience. You can float from inside a volcano to the ocean, past spectacles of wildlife and geology. From Surprise Lake, the river flows a peaceful mile to The Gates. The river moves swiftly through this narrow gorge in the caldera wall, and large rocks demand precise maneuvering. A gradient of 75 feet per mile makes this section challenging. After a more gentle 10 miles comes the confluence with Hidden Creek, and the river is again filled with car-sized boulders, abrupt bends, and a narrow bed requiring extreme caution. After 5 more miles, the river slows to meander toward the Pacific Ocean and the seals, sea otters, bald eagles, and sea birds of Aniakchak Bay.

Those who head down the river, though, had best be prepared and skilled in navigating whitewater.

Rafting the Aniakchak River is a great reason to visit this remote park unit/NPS

"Total float time: three to four days from Surprise Lake to the bay. Camp on sandy gravel bars for flat tent sites and fewer bugs — and so that your human impacts are readily erased by subsequent high water. Use a small backpacking stove; firewood is scarce in treeless tundra," the park suggests. "Only a few parties float the river each year, mostly in July. Plan on delays getting in and, especially, delays getting out. Dry suits are recommended; life jackets are required. Scout The Gates and Hidden Creek confluence before you run them. Inflatable rafts 12 or 13 feet long with rowing platforms are most popular. And, be sure to bring lots of repair materials!"