The United States is home to a diverse collection of forest systems, covering hundreds of millions of acres across the continent. These vast woodlands, ranging from temperate rainforests to expansive pine and hardwood stands, represent significant biological wealth. To identify the largest areas, this article examines the immense tracts of land officially managed for conservation, timber, and recreation. It details the seven largest forest regions, based on the acreage of the major administrative units that govern them, and their locations.
Clarifying the Scope of “Largest Forests”
Defining the single “largest forest” in the U.S. is complex because forest land is measured in multiple ways. A forest can be viewed as a contiguous ecological region, a privately held timber area, or an official administrative unit like a National Forest. The boundaries of ecological regions are often fluid and difficult to quantify, whereas private holdings are fragmented.
For the purpose of identifying the largest areas, the most reliable metric is the total acreage of the largest National Forests, which are legally defined and managed by the U.S. Forest Service. These administrative units often encompass an entire mountain range or a significant portion of a major ecosystem. Focusing on these units provides a clear and verifiable list of the nation’s most extensive public forest holdings.
The Largest Forest Regions of the Western United States and Alaska
The largest forest areas are found in the Western U.S., particularly in Alaska, where National Forests cover millions of acres of largely undeveloped terrain. These immense tracts of land represent some of the most intact and ecologically significant ecosystems remaining globally.
The Tongass National Forest in Southeast Alaska is the largest National Forest in the United States, spanning approximately 17 million acres. This colossal expanse is a temperate rainforest, featuring towering Sitka spruce and western hemlock trees, and is a major carbon sink. Its location encompasses the islands of the Alexander Archipelago and the mountainous coastline, making it a landscape of fjords, glaciers, and productive salmon streams.
The Chugach National Forest, also located in Alaska, covers about 6.9 million acres in the south-central part of the state. It is the northernmost and westernmost National Forest, characterized by rugged alpine terrain, coastal rainforests, and extensive wetlands like the Copper River Delta. Roughly 30 percent of the forest is covered by ice, including numerous tidewater glaciers that flow into Prince William Sound.
The largest National Forest in the contiguous United States is the Humboldt-Toiyabe National Forest, which sprawls across 6.3 million acres in Nevada and California. This forest is characterized by a diverse range of landscapes, from high desert sagebrush to alpine peaks in the Sierra Nevada mountains. The forest is unique for comprising multiple non-contiguous units, protecting 23 separate wilderness areas across its acreage.
The Salmon-Challis National Forest in central Idaho covers approximately 4.3 million acres of mountainous terrain. This area contains a significant portion of the Frank Church-River of No Return Wilderness, the largest continuous wilderness area in the lower 48 states. The forest is defined by the Salmon River, which has carved deep canyons through the region.
Significant Forest Areas in the Eastern and Southern U.S.
While the Western National Forests dominate the overall size rankings, the Eastern and Southern U.S. contain massive and ecologically distinct forest areas. These forests, often closer to large population centers, provide vital recreational and watershed protection resources.
The Superior National Forest in northeastern Minnesota is the largest National Forest in the Eastern Region, encompassing nearly 3.9 million acres. It is home to the Boundary Waters Canoe Area Wilderness, a federally protected area known for its network of pristine lakes and boreal forest. This forest plays a significant role in managing the region’s vast water resources and supporting an extensive ecosystem of moose, wolves, and black bears.
The George Washington and Jefferson National Forests represent the largest public land area in the Southern Appalachian Mountains, combining for approximately 1.8 million acres. This forest system spans across Virginia, West Virginia, and a small part of Kentucky, protecting a mix of hardwood and conifer forests. It is an important source of water for major river systems and hosts diverse wildlife populations, including the federally endangered Red-cockaded Woodpecker in its southern reaches.
The Ouachita National Forest is another extensive Southern forest, covering about 1.78 million acres primarily in western Arkansas and extending into eastern Oklahoma. Established in 1907, it is the oldest National Forest in the Southern United States and is dominated by shortleaf pine and hardwood species. The forest is managed for water quality, timber production, and recreation, offering a vast network of trails through the Ouachita Mountains.