The courthouse, which was designed by Michael Priestley in the neoclassical style and built in ashlar stone, was completed in 1746.

[1] The design involved an asymmetrical main frontage with eight bays facing The Diamond; the central bay featured a doorway with a banded stone surround and a pediment; there was a stone panel containing the coat of arms of George II above the doorway.

[8] The gallows, at the front of the new gaol, were also the setting for the infamous 'half-hanging' of John 'Half-Hung' MacNaghten, in one of the earliest recorded public hangings at the courthouse in 1761.

Just as in many other prisons throughout Ireland, this usually consisted of breaking stones which were then used to build and repair roads, or grinding up bones, which would then be used as fertilizer.

The building also now houses a bistro, a local library, conference rooms and often hosts special events.