[5] The structure was extended northwards, at the expense of Henry Somerset, 6th Duke of Beaufort, by the creation of a narrow single-story northern block of six bays, in 1816.

The extra floor on the southern block, which was erected to accommodate a lofty council chamber for the burgesses, was fenestrated by five segmentally-headed sash windows and five distinctive oculi overlooking Old Market Street.

Meanwhile, the extra floor on the northern block, which involved a central section of four bays which was slightly projected forward and pedimented, was fenestrated by plain sash windows.

[7] The 8th Monmouthshire Rifle Volunteer Corps was raised in Usk in October 1860 and paraded in front of the town hall before being sent on a march to Raglan Castle.

[16] A monument, in the form of a granite column surmounted by an urn, which was intended to commemorate the lives of local service personnel who had died in the Second Boer War, was unveiled to the north of the town hall by the former portreeve of the borough, James Henry Clark, in 1908.