The first town hall in Monaghan was a narrow, terraced building commissioned by Derrick Westenra, 5th Baron Rossmore which faced onto The Diamond.

[1] It was designed by William Hague in the Italianate style, built in red brick with stone dressings and was completed in September 1882.

It was surmounted by a modillioned pediment with a coat of arms of the Westenra family, carved in red sandstone, in the tympanum.

[5] After the council moved out of the building in 1929, it was used as a cinema,[6] and later served as a function suite for the adjacent Westenra Arms Hotel.

[13] A further major programme of refurbishment works was subsequently carried out by Demac Construction at a cost of €1.25 million to a design by Keys and Monaghan Architects.