The future of detention facilities in counties Cork, Wicklow, Cavan and Kildare are under threat.
Curragh
The Co Kildare prison held an average of 92 inmates every day last year, despite the fact it was designed to hold just 68 prisoners. It is a former military detention centre and was opened as a prison in 1996.
Its population is comprised mainly of sex offenders aged 30 or over. Many of the prisoners are priests or former priests serving sentences for child sex abuse.
Some 75 prison officers are employed at the closed, medium-security facility. The cost of keeping a prisoner at the Curragh last year was 72,400, the eighth most expensive of the State's 16 prisons.
Around 75 per cent of inmates participate in educational activities, with 27 inmates last year pursuing accredited academic courses including the Senior Cert and Open University Courses.
Fort Mitchell (Spike Island)
Situated in Cork Harbour, Fort Mitchell is a closed, medium security prison for the detention of young males usually aged between 16 and 24. It is a former naval base and has been a civilian prison since 1985.
Last year the average number of prisoners in custody was 84, although it can hold up to 102 inmates.
It is regarded as one of the prison service's best male facilities. More than 85 per cent of inmates participated in educational programmes last year. Some 45 inmates completed the drugs awareness programme, with 37 completing the pre-release course.
There are 93 prison officers employed at Fort Mitchell. The cost of keeping a prisoner in custody last year was 100,100, the third highest per prisoner cost in all of the Republic's prisons.
Loughan House
Located in Blacklion, Cavan, it is an open place of detention for convicted male offenders aged 18 or over. A former seminary, it opened as a penal institute in 1972.
It held an average of 70 inmates each day last year, with an additional 15 on temporary release. Its bed capacity is 85, comprising mainly single and double bedrooms.
All of the inmates pose a low security risk and many are nearing the end of lengthy sentences. About half of the inmates attended educational courses last year. Prisoners are allowed to leave the grounds and mix with the local community. A small number of them work locally.
Around 49 prison officers are employed at the facility. The cost of detaining a prisoner there last year was 62,850, making it the second least expensive place of detention in the State.
Shelton Abbey
The Co Wicklow facility is an open detention centre for male offenders aged 19 or over. It opened in 1973. Prisoners are sent there from closed prisons to complete their sentences. Most long-term prisoners complete their sentences in Shelton Abbey, where they are prepared for eventual release. It has a bed capacity of 58. The average daily number in custody last year was 47.
About 75 per cent of prisoners participated in educational programmes last year, including basic literacy and numeracy, information technology and Open University courses.
Some 45 prison officers are employed at the facility. The cost of detaining a prisoner in Shelton Abbey last year was 84,850, making it the seventh most expensive of the State's 16 prisons.