HM Prison Dartmoor

HM Prison Dartmoor is a Category C men's prison, located in Princetown, high on Dartmoor in the English county of Devon. Its high granite walls dominate this area of the moor. The prison is owned by the Duchy of Cornwall, and is operated by His Majesty's Prison Service.

The prison closed temporarily in 2024 for radon mitigation and investigation works.

Dartmoor Prison was given Grade II heritage listing in 1987.

In 1805, the United Kingdom was at war with Napoleonic France, a conflict during which thousands of prisoners were taken and confined in prison "hulks" or derelict ships. 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.

The prison was designed by Daniel Asher Alexander. Construction by local labour started in 1806, taking three years to complete. In 1809, the first French prisoners arrived and the prison was full by the end of the year.

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). These were either naval prisoners or impressed American seamen discharged from British vessels. Whilst the British were in overall charge of the prison, the prisoners created their own governance and culture. They had courts which meted out punishments, a market, a theatre and a gambling room. About 1,000 of the prisoners were Black. 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."

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. Local residents turning in an escapee could expect a reward of a guinea. Yet, despite these daunting odds, scholar Nicholas Guyatt has tallied a total of twenty-four American POWs successfully making their way to freedom.

Although the war ended with the Treaty of Ghent on 24 December 1814, American prisoners of war remained in Dartmoor because the British government refused to grant them parole or to take any steps until the treaty was ratified by the United States Senate on 17 February 1815. It took several weeks for the American agent to secure ships for their transportation home, and the men grew very impatient. On 4 April, a food contractor attempted to work off some damaged hardtack on them in place of soft bread, but was forced to yield by their insurrection. The commandant, Captain T. G. Shortland, suspected them of a design to break out of the gaol. This was the reverse of the truth in general, as they would lose their chance of going on the ships, but a few had made threats of the sort, and the commandant was very uneasy.