This was considered a security risk, partially due to the proximity of the Royal Naval dockyard at Devonport (then called Plymouth Dock) and living conditions were appalling in the extreme; consequently, a prisoner of war depot was planned in the remote isolation of Dartmoor.

[5] From the spring of 1813 until March 1815, about 6,500 American sailors from the War of 1812 were imprisoned at Dartmoor in poor conditions (food was bad and the roofs leaked).

[7][8] A recent examination of the General Entry Book of American Prisoners of War at Dartmoor, by Nicholas Guyatt, found "Eight Hundred and Twenty - Nine Sailors of Colour had been entered into the register by the end of October 1814.

"[9] Unlike many detention facilities of the period, Dartmoor Prison was purpose built in an isolated location, ringed by high stone walls, and manned by hundreds of armed militia sentries.

In addition a rope ran around the entire circumference of the prison, linked to a series of bells, which quickly spread an alarm.

Even if a determined prisoner made it beyond the walls, he would still have to traverse ten miles on foot, over wild moorland and bogs, an area frequently beset with fog and chilling winds, to reach the nearest town.

[11] Yet, despite these daunting odds, scholar Nicholas Guyatt has tallied a total of twenty-four American POWs successfully making their way to freedom.

On 4 April, a food contractor attempted to work off some damaged hardtack on them in place of soft bread and was forced to yield by their insurrection.

The crowd yelled louder and threw stones, and the soldiers, probably without orders fired a direct volley which killed and wounded a large number.

[8] Finally the captain, a lieutenant and the hospital surgeon (the other officers being at dinner) succeeded in stopping the shooting and started caring for the wounded – about 60, 30 seriously, besides seven killed outright.

The affair was examined by a joint commission, Charles King for the United States and F. S. Larpent for Great Britain, which exonerated Shortland, justified the initial shooting and blamed the subsequent deaths on unknown culprits.

During the First World War in 1917, criminals were removed from the gaol when it was converted into a Home Office Work Centre for conscientious objectors granted release from other prisons.

[17] Dartmoor continues to suffer from its age, in 2001 a Board of Visitors report condemned sanitation, as well as highlighting a list of urgent repairs needed.

[24] In March 2008, staff at the prison passed a vote of no confidence in the governor Serena Watts, claiming they felt bullied by managers and unsafe.

Full-time employment is also available in catering, farming, gardening, laundry, textiles, Braille, contract services, furniture manufacturing and polishing.

The "Dartmoor Jailbreak" is a yearly event, in which members of the public "escape" from the prison and must travel as far as possible in four days, without directly paying for transport.

[31] It was announced in October 2019 that HMP Dartmoor would close in 2023,[32] but in December 2021 it was confirmed that, following negotiations with the Duchy, it would remain open beyond 2023 and for the foreseeable future.