The flanking wings were extended forward in the 1960s.
The courthouse was substantially upgraded in 2009. The brief was for an upgrading of the main courtroom and the construction of an additional courtroom to cater for civil and family hearings. The project also included the provision of judge's chambers, offices for the County Registrar and the District Court, legal practitioner’s room, consultation rooms, victim support room and holding cells for prisoners. The refurbishment means that the sittings of the Circuit and District courts can run simultaneously.
Thurles Courthouse is supported by Nenagh District Court Office.