Police and firefighters were called to a blaze at Karnet Prison Farm in Keysbrook overnight.
The fire started in a mechanical workshop at the low-security facility around 10pm.
It took fire crews over an hour to extinguish the blaze.
All inmates and prison staff have been accounted for and police say there are no suspicious circumstances.
Long-term Pinjarra resident gifts Shire heritage railway carriages, brake vans
The Shire of Murray has been gifted nine heritage railway carriages and four heritage brake vans from long-term Pinjarra resident Colin Taylor, as a contribution towards the Pinjarra Heritage Railway Precinct Project.
Extent of damage to Bar Therapy following devastating fire revealed
The extent of the damage to a Mandurah bar after a fire tore through the heritage-listed building has been revealed.
MARC pool reopening date announced after three year closure
It has taken three years to fix, but the 25-metre indoor pool at the Mandurah Aquatic and Recreation Centre (MARC) will reopen on May 6.
Yunderup Island blaze under control
Firefighters have spent the night battling a ferocious bushfire on Yunderup Island in South Yunderup.
Mandurah's Bar Therapy damaged by fire
Mandurah's Bar Therapy has been damaged by fire.
Postman injured in Wannanup crash
A postman has been taken to hospital following a crash in Wannanup.
Man charged after allegedly stealing service medals from Greenfields storage unit
Mandurah Police are asking for the public's help to recover a stolen set of service medals.
South West resort receptionist charged with 32 fraud offences
A South West resort employee has been charged after allegedly using guests credit card details to purchase items and accessing the retreat's eftpos machine to refund money into her own bank account.
Daughter of Port Kennedy hit-and-run victim pleads for offenders to hand themselves in
The daughter of a Port Kennedy hit-and-run victim is pleading for the two offenders to hand themselves in.