The following text dates from 1911. Much of it needs to be updated.
The Adirondacks are a group of mountains in north-eastern New York, U.S.A., in Clinton, Essex, Franklin and Hamilton counties, often included by geographers in the Appalachian system, but pertaining geologically to the Laurentian highlands of Canada. They are bordered on the east by Lake Champlain, which separates them from the Green Mountains.
A large portion of the Adirondack range is encompassed within the constitutionally protected 6 million acres of Adirondack State Park, which includes a forest preserve of approximately 2.3 million acres. The Adirondacks contain a number of lakes, including Lake Placid, two-time site of the Olympic Winter Games.
Unlike the Appalachians, the Adirondacks do not form a connected range, but consist of many summits, isolated or in groups, arranged with little appearance of system. There are about one hundred peaks, ranging from 370 m to 1500 m (1200 to 5000 ft.) in height; the highest peak, Mt. Marcy (called by the Indians Tahawus or "cloud-splitter"), is near the eastern part of the group and attains an elevation of 1629 m (5344 ft). Other noted peaks are McIntyre, 1588 m (5210 ft), Haystack 1499 m (4918 ft.), Dix 1498 m (4916 ft.) and Whiteface 1485 m (4871 ft).
These mountains, consisting of various sorts of gneiss, intrusive granite and gabbro, have been formed partly by faulting but mainly by erosion, the lines of which have been determined by the presence of faults or the presence of relatively soft rocks. Lower Palaeozoic strata lap up on to the crystalline rocks on all sides of the mountain group. The region is rich in magnetic iron ores, which though mined for many years are not yet fully developed (Is this still true?). Other mineral products are graphite, garnet used as an abrasive, pyrite and zinc ore.
The mountains form the water-parting between the Hudson and the St. Lawrence rivers. On the south and south-west the waters flow either directly into the Hudson, which rises in the centre of the group, or else reach it through the Mohawk. On the north and east the waters reach the St. Lawrence by way of Lakes George and Champlain, and on the west they flow directly into that stream or reach it through Lake Ontario. The most important streams within the area are the Hudson, Black, Oswegatchie, Grass, Raquette, Saranac and Ausable rivers.
The region was once covered, with the exception of the higher summits, by the Laurentian glacier, whose erosion, while perhaps having little effect on the larger features of the country, has greatly modified it in detail, producing lakes and ponds, whose number is said to exceed 1300, and causing many falls and rapids in the streams. Among the larger lakes are the Upper and Lower Saranac, Big and Little Tupper, Schroon, Placid, Long, Raquette and Blue Mountain. The region known as the Adirondack Wilderness, or the Great North Woods, embraces between 13,000 km2 and 16,000 km2 (5000 and 6000 square miles) of mountain, lake, plateau and forest, which for scenic grandeur is almost unequalled in any other part of the United States.
The next paragraphs are truly dated. What can be updated, what needs to go?
The mountain peaks are usually rounded and easily scaled, and as roads have been constructed over their slopes and in every direction through the forests, all points of interest may be easily reached by stage. Railways penetrate the heart of the region, and small steamboats ply upon the larger lakes. The surface of most of the lakes lies at an elevation of over 1500 ft. above the sea; their shores are usually rocky and irregular, and the wild scenery within their vicinity has made them very attractive to the tourist. The mountains are easily reached from Plattsburgh, Port Kent, Herkimer, Malone and Saratoga Springs. Every year thousands spend the summer months in the wilderness, where cabins, hunting lodges, villas and hotels are numerous. The resorts most frequented are in the vicinity of the Saranac and St Regis lakes and Lake Placid.
In the Adirondacks are some of the best hunting and fishing grounds in the eastern United States. Owing to the restricted period allowed for hunting, deer and small game are abundant, and 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 may be obtained. Two miles south-east of this lake, at North Elba, is the old farm of the abolitionist John Brown, which contains his grave and is much frequented by visitors. Lake Placid is the principal source of the Ausable river, which for a part of its course flows through a rocky chasm from 100 to 175 ft. deep and rarely over 30 ft. wide. At the head of the Ausable Chasm are the Rainbow Falls, where the stream makes a vertical leap of 70 ft.
Another impressive feature of the Adirondacks is Indian Pass, a gorge about eleven miles long, between Mt. McIntyre and Wallface Mountain. The latter is a majestic cliff rising vertically from the pass to a height of 1300 ft. Keene Valley, in the centre of Essex county, is another picturesque region, presenting a pleasing combination of peaceful valley and rugged hills. Though the climate during the winter months is very severe--the temperature sometimes falling as low as -42 degrees F, a number of sanitariums were located there in the early 1900s. The region is heavily forested with spruce, pine and broad-leaved trees. Lumbering is an important industry, but it has been much restricted by the creation of a state forest preserve (this is Adirondack State Park, which is discussed above.)
All of these resources need to be updated
For a description of the Adirondacks, see S. R. Stoddard, The Adirondacks Illustrated (24th ed., Glen Falls, 1894); and E. R. Wallace, Descriptive Guide to the Adirondacks (Syracuse, 1894). For geology and mineral resources consult the Reports of the New York State Geologist and the Bulletins of the New York State Museum.
Initial text from 1911 encyclopedia -- Please update as needed