Portlaoise Prison (Irish: Príosún Phort Laoise) is a maximum security prison in Portlaoise, County Laois, Ireland. Until 1929 it was called the Maryborough Gaol. It should not be confused with the Midlands Prison, which is a newer, medium security prison directly beside it; or with Dunamaise Arts Centre, which was the original Maryborough Gaol built c. 1789. A number of IRA and dissident republican prisoners are housed in "E Block". Anyone charged under Section 30 of the Offences Against the State Act must be sent to the prison because of its unique security measures.