The Court House opened in November 1858 but within four years it became inadequate for current needs.
In June 1862 tenders were called for substantial renovation and expansion of the near new building, so it could also house a troop of Mounted Police that was to be stationed in Paterson. The roof was removed and the walls raised to two storeys to accommodate a troopers' barracks above the cells and police quarters. At the same time the court-room was extended, with a vestibule in front, and two wings were added to provide a jury room and a magistrates' room. Provision was also made for future extension in the form of an additional room in each wing. As part of this work, stables were constructed at the rear of the court house for the troopers' horses.
Paterson was the centre for administration of justice in the Paterson Valley until the local Court of Petty Sessions was discontinued in 1967.