The mountains are often included by geographers in the Appalachian Mountains, but they pertain geologically to the Laurentian Mountains of Canada. They are bordered on the east by Lake Champlain and Lake George, which separate them from the Green Mountains in Vermont. They are bordered to the south by the Mohawk Valley and to the west by the Tug Hill Plateau, separated by the Black River. This region is south of the St. Lawrence River.
Hunting and fishing are allowed in the Adirondack Park, although in many places there are strict regulations. Because of these regulations, the large tourist population has not over fished the area, and as such, the brooks, rivers, ponds and lakes are well stocked with trout and black bass. At the head of Lake Placid stands Whiteface Mountain, from whose summit one of the finest views of the Adirondacks can be obtained. Two miles (3 km) southeast of this lake, at North Elba, is the old farm of the white abolitionist John Brown, which contains his grave and is frequented by visitors. Lake Placid outflow is a major contributor to the Au Sable River, which for a part of its course flows through a rocky chasm 100 feet to 175 feet (30 m to 53 m) deep and rarely more than 30 ft (10 m) wide. At the head of the Ausable Chasm are the Rainbow Falls, where the stream makes a vertical leap of 70 ft (20 m).
Another impressive feature of the Adirondacks is Indian Pass, a gorge about eleven miles (18 km) long between Mt. McIntyre and Wallface Mountain. The latter is a majestic cliff rising from the pass to a height of 1300 ft (400 m). Keene Valley, in the center of Essex County, is another picturesque region, presenting a pleasing combination of peaceful valley and rugged hills.
Although the climate during the winter months is very severe, with absolute temperatures often falling into the −30 °F (−35 °C) range (pre wind chill), a number of sanitariums were located there in the early 1900s because of the positive effect the air had on tuberculosis patients. The region is heavily forested with spruce, pine and broad-leafed trees. Lumbering, once an important industry, has been much restricted since the creation of the State Park, more than 100 years ago.