forest region and wilderness area in southeastern Alaska, U.S., on the Gulf of Alaska. Established in 1909 by a bill passed in Congress and signed into law by President Theodore Roosevelt, the Tongass National Forest covers most of the Alaska panhandle and is the largest publicly owned forest in the United States. Its 16,800,000 acres (6,800,000 hectares), composed of mountainous offshore archipelagos and rugged fjord-indented coastline, include some of the most extensive intact remnants of virgin temperate rain forest in North America.

Found in association with barren alpine tundra (above the tree line), lowland muskeg, and scores of tidewater glaciers that descend to the coastline, the forest is dominated by towering species of western hemlock and Sitka spruce. Its rich understory includes blueberry, skunk cabbage, and a profusion of ferns and mosses. Brown and black bears, Sitka black-tailed deer, wolves, mountain goats, river otters, mink, northern flying squirrel, seals, and numerous species of birds, including bald eagles and the elusive marbled murrelet, are part of the unusual variety of wildlife. In 1980 about one-third of the Tongass—long a region of intense conflict between conservationists and logging companies—was designated a national wilderness area.