Dartmoor is a great granitic upland in Devonshire, the source, with two exceptions, of all the principal rivers of the county, remarkable alike for its wild and rugged scenery, its antiquities, its wide, solitary, trackless wastes, and its mineral products. It is upwards of 130,000 acres in extent, the extreme length from north to south being 25 miles, and the extreme breadth from east to west 20 miles. The outline is irregular. The central portion is the ancient royal forest of Dartmoor, and this is surrounded by a belt of open country, once known as the 'Commons of Devonshire,' but portions of which have been inclosed. The attempts to cultivate Dartmoor itself have been very few, and the northern quarter for miles shows no trace of man, but the valleys through which the rivers descend to the lowland country are singularly fertile, and at times full of beauty. The moor itself affords valuable mountain pasture to cattle, sheep, and large numbers of half-wild ponies. The forest rights belong to the duchy of Cornwall; but there are rights of pasturage exercised by holders of what are called venville tenures in certain parishes bounding the moor, which date prior to the Norman Conquest.
The average height of Dartmoor above the sea is upwards of 1200 feet, but its highest point, High Willhayes, is 2039 feet; and the next, Yes Tor, 2030. The hills are commonly called tors, and for the most part have granite crests, weathered into grotesque and picturesque shapes. The whole of Dartmoor is of granite, protruded between the close of the Carboniferous and the opening of the Triassic periods. Devonian rocks mantle round its southern extension, and Carboniferous round its northern, associated at various points with gabbros, dolerites, and other intrusive rocks. The granite is chiefly gray, but there are rich red varieties, as at Trowlesworthy. Large quantities of the ordinary stone have been quarried, especially at Hey Tor and King Tor. Dartmoor is rich in minerals. Tin has been raised for many centuries, long before the dawn of history, by streaming in the valleys, and vestiges of the ancient mining operations of the 'old men' abound. Copper, iron, and manganese have also been worked, but mining is now carried on at a few points only. Gold has frequently been found in the river-beds. The tinners of Devon had a quasi-corporate existence in Saxon times, and their rights were confirmed by King John and other monarchs. The Stannary Parliaments, in which they managed their affairs, were held in the open air on Crockern Tor. The most important mineral product of Dartmoor at the present day is china-clay, or kaolin, which is the result of the decomposition of the felspar of the granite. The largest china-clay works in England are at Lee Moor, and are connected by a tramway with wharves at Plymouth.
The fauna and flora of Dartmoor have many points of interest. Trees are very rare; but there is a very singular group of gnarled and stunted oaks on a slope overlooking the West Dart, near Crockern Tor, of high antiquity and weird aspect, which has been called one of the 'wonders of the moor'—'Wistman's Wood.'
The chief rivers rise at a height of over 1800 feet above the sea, in a wide stretch of peat-bog around Cranmere Pool—the Dart, Teign, Taw, Ockement, Lyd, Tavy, and Walkham. From the morasses of the southern quarter spring the Plym, Yealm, Erme, and Avon.
Dartmoor is unrivalled in England in the extent and character of its prehistoric and rude stone antiquities—earthworks, barrows, kistvaens, menhirs, lines or avenues, cyclopean bridges, circles, cromlechs, trackways, and pounds or inclosures of stones, sometimes containing the remains of villages. Many stone implements have been found. On several of the tors there are rock basins, formerly called Druidical, but now assigned to the operation of natural causes.
The chief centre of population is Prince Town, named after George IV. when Prince Regent. Here a prison was built (1806) during the war with Napoleon, for the reception of prisoners of war. When the war ended it was abandoned, and was at one time used for the manufacture of naphtha from peat, which failed. In 1855 the buildings were adapted to their present purpose of a convict prison. Attached is a fertile reclaimed farm.
A very picturesque railway runs to Prince Town. See Rowe's Perambulation of Dartmoor (1856; 3d ed. 1896); Beatrix F. Cresswell, Dartmoor and its Surrounding (1900); and Baring-Gould, A Book of Dartmoor (1900).