Although the present building has been altered in the C18th and C19th it still retains much of its original 1572 structure. It is stone-built with a slate roof and of 2-storeys. It was restored in 1780 with tripartite stone mullion windows to first-floor and re-roofed, by raising the eaves level and flattening the pitch. Windows were inserted between the ground-floor open columns and a lean-to was added in stages to the south side.
The ground-floor would have originally been used as a market area and was open to front and rear. The first-floor would have housed a meeting room or courthouse and is now the Denbigh town library. On the ground-floor there were once two groups of three openings supported by columns to each facade and they are largely in-situ. The front north wall has windows in the openings. The rear wall was similar, although only three columns are visible and the lean-to has obscured most evidence.
The first-floor was supported on ceiling-beams resting on a spine of eight columns, seven are still visible. The only original features are the blocked window openings, visible externally, those tothe west end indicate these were pairs of windows.
In the attic one original roof-truss was retained when the roof was raised with new King-post tie-beam and strut trusses. The original truss has a tie-beam, three studs and collar with raking-struts. There are recesses for three side-purlins to each principal-rafter and a diagonally-set ridge. This was a closed truss with auger holes and `v' shape grooves for wattle and daub in-fill. The timbers were dendro-dated to a felling date of 1571, confirming they were original to the buiding's documented date of 1572.
Geoff Ward, visited, 02/02/2005.

County Hall, originally constructed c.1572, supposedly on land donated by Robert Dudley, Earl of Leicester, from whom a letter survives, written to the Bishop of St Asaph urging the construction of the Hall. This original building was constructed of rubble stone, with two open arcades of three arches each along the north side at ground floor level. The arcades were supported by moulded columns, and were almost certainly replicated along the south side of the buildings, making the ground floor an open market spce freely accessible from both streets flanking the length of the hall. The facade of the building was probably at the west end, facing the High Street, as does the current front, but little of its form survives.

In the 1780s a major programme of repair and reurbishment took place, including the heightening of the external walls and the replacing of the roof. Much of this work is detailed in documents held by the Denbigh County Record Office. The majority of the window openings were replaced with plain stone mullioned windows, with a stone Venetian window inserted into the west facade, and a further two (one in each of the north and south elevations) lighting the east bay of the first floor chamber.

In the 19th century a single storey extension was constructed against the west end of the south elevation. This had a curved western end, arcing round to the West facade, and acted as a Police lock-up with at least two cells, serving the Magistrates court. In the first half of the 20th century this extension was extended the length of the Hall. Both the 19th and 20th build copied the style of the 1780 structure, with the windows replicating the form of the mullions, and the use of a projecting plinth. Many of the openings in the south extension were blocked and new ones formed during a programme of remodelling in the late 20th century, when the Hall was converted into a library. The interior of the building was completely refurbished, a lift shaft inserted to access the first floorand the surviving arcades in the north elevation glazed to form large plate glass windows.
Visited August/September 2005 S Fielding