The Department of Home Affairs says the prison has almost 15 per cent more inmates than it was designed for.
A Freedom of Information request asked how many prisoners the Jurby facility was designed to hold, and how many people were currently incarcerated there.
In its response, the department said the official capacity was 141 - and on April 7 there were 159 inmates.
It added there were 26 cabins on top of the permanent accommodation, all of which were being used.
Illegal pet put down after being seized by government
The government says an illegally-imported XL Bully dog has been put to sleep.
Castletown Living Streets scheme 'paused', says minister
Infrastructure Minister Michelle Haywood says a scheme to improve Castletown's streets has been put on hold.
Cregneash buses to be raised in Keys
A bus route to one of the Island's beauty spots will be raised in the House of Keys next week.
Second Mountain Road closure today after spill
The Department of Infrastructure says it needs to close the Mountain Road tonight as it resurfaces more than 200 metres.
Commissioners unveil detailed plans for 260-person venue on promenade
Peel commissioners have unveiled detailed plans for a huge new venue near the town's bowling greens, which could hold up to 260 people and 10 staff.
Liverpool agreement didn't hand anything to Merseyside, says chief minister
Chief Minister Alf Cannan says an agreement signed with Liverpool is a way to learn from each other.
What would make you visit Douglas more often?
An organisation which promotes and helps the Island's capital is asking for your views.
Commissioners announce wildflower scheme in Ramsey
Ramsey commissioners say they'll show their commitment to the environment by not mowing the grass.
