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.
Business appeal over thousands in unpaid bills
A business in Douglas is asking customers to pay their bills - as it chases more than £5,500 in outstanding accounts.
Pharmacy plans for former IOM Bank
A pharmacy's applied for planning permission to put signs up on a former bank in Peel.
Appeal after wood from van damages car
A man's appealing for information after a van driver's load damaged his partner's car.
Island part of union data breach investigation
The Island's information commissioner is taking part in an investigation into a huge data breach at a trade union.
Cracked pipe closes NSC pool
The main swimming pool at the National Sports Centre in Douglas has closed this morning.
Island updates arms export rules
The Island's updated its export controls to match the latest European and UK regulations.
Onchan Raceway to stay open with new lease
Onchan commissioners say Onchan's raceway will remain in operation after the company agreed to sign a new lease.
Jobcentre can't stop ads being doubled up
Treasury Minister Alex Allinson says there's no way of ensuring job ads in the Island's Jobcentre aren't doubling up.
