[2] After the opening of HMP Dartmoor in 1809, the battalion of soldiers guarding the around 5,000 prisoners there began practising musketry at a firing range at Hart Tor.

Four years later, a major exercise was held by the First and Second Divisions, involving over 12,000 men and 2,100 horses, in the Ringmoor, Roborough and Yennadon Downs area.

[3]: 2 During this time, the nation's main artillery training area was at Shoeburyness, where the guns fired out to sea.

The War Office agreed with the Duchy of Cornwall and the town council of Okehampton to set up a training range in north Dartmoor.

The first temporary camp was established in 1875 on Halstock Down and artillery firing between the East Okement and Taw Rivers lasted for three weeks.

Over the next years the number of field and horse artillery that came to the area steadily increased until training went on throughout the summer months.

[3]: 3 Although the people of Okehampton appreciated the additional business brought by the troops, the graziers protested as the livestock was driven off.

In the 1920s this land was turned into rifle, grenade and field firing ranges and the core of a camp for the troops using these facilities.

As war with Germany became likelier, Territorial Army units were mobilized and the Devonshire Yeomanry finalized their training here.

A new rifle range on Rippon Tor was built, an airfield constructed on Roborough Down and another camp of Nissen huts was started at Plasterdown (later to become a hospital for U.S. forces).

[3]: 9 In the year before the June 1944 Invasion of Normandy, the 4th and 29th U.S. divisions trained on Dartmoor, with thousands of troops living in camps along the roads all across the moor.

Mons and Eaton Hall Officer Cadet Training Units set up battle schools at Okehampton Camp.

[3]: 10 Units, including some tanks, mobilised for the Suez Crisis in 1956 trained on Dartmoor, operating briefly in the Yes Tor area.

[3]: 10 In 1963 the Dartmoor Preservation Association (DPA) published a 24-page booklet entitled Misuse of a National Park which includes photographs of unexploded shells lying on the open moor, corrugated iron buildings, large craters, a derelict tank used as a target, bullet marks on standing stones, etc.

[3]: 11 In 1975/6, a local public inquiry by Lady Sharp into the continued use of Dartmoor by the military for training purposes found no viable alternative, but regular consultation between the Ministry of Defence, the National Park Authority and other interested parties was suggested.