Gates of the Arctic National Park and Preserve, one of the finest wilderness areas in the world, straddles the Arctic Divide in the Brooks Range, America's northernmost chain of mountains. Second only to Wrangell-St. Elias National Park in size, Gates of the Arctic covers 13,238 square miles, sprawls 800 miles from east to west and is entirely north of the Arctic Circle. Most of the park is a maze of glaciated valleys and gaunt, rugged mountains covered with boreal forest or treeless slopes of Arctic tundra north of the divide. It is a habitat for grizzly bears, wolves, Dall sheep, moose, caribou and wolverines. Fishing is considered superb for grayling and Arctic char in the clear streams and for lake trout in the larger, deeper lakes. The remoteness of the park attracts mostly experienced backcountry travellers for float trips, backpacking treks or base camps set up to enjoy day hiking and fishing. Many visitors join guided trips that a handful of outfitters offer in summer for rafting and hiking or in the winter for dog mushing and cross-country skiing. Either as an independent traveller or as part of guided expedition, a visit to Gates of the Arctic requires careful planning and advance reservations.