Ballycastle Museum (former court house), 59 Castle Street, Ballycastle, County Antrim, BT54 6AR

Ballycastle Museum, formerly a court house and market house, is a domestically scaled, relatively plain two-storey terrace building on the south side of Castle Street, to the west of Ballycastle town centre. It probably dates from the mid-18th century, most likely the 1740s, and is one of the rare surviving examples of a street-bound court and market house in Ulster, as well as one of Ballycastle's most important pieces of built heritage.

The asymmetrical north-facing front elevation is finished in painted lined render with a bevelled base course, a ground floor string course at arch-springing level, and a deeper string course between the ground and first floors. Just left of centre is the main entrance: a large timber-sheeted double door with a large three-pane segmental fanlight, set within a semicircular-headed recess with keystone, which was originally open. To its left is an identical recess, also with a timber-sheeted door, though this one is no longer in use. To the right of the entrance, what was once a third identical archway has been converted to a window, with a mullioned timber frame containing three elliptical-headed lights and a fanlight above, matching the others in form. Further right is a narrower, domestic-scale doorway with a panelled timber door. At first floor level there are three relatively narrow, unevenly spaced windows with horned timber sash frames of six over six panes, set in relatively broad boxes. Between the main entrance and the converted window there is a traditional-style projecting signboard, and a projecting street lamp sits between the first and second first-floor windows.

The rear of the building is dominated by a large full-height gabled return set slightly west of centre. On the west face of the return, at first floor level, there is a lean-to extension containing two windows with modern timber frames. To the right of the lean-to, still on the west face of the return proper, is another window with a timber sash frame matching those at the front. On the south-facing gable of the return, the ground floor has a large flat-arch doorway with metal double doors at its centre. At first floor level to the right of this is an unusual, roughly square window of three semicircular-headed lights with lattice panes, moulded sandstone mullions, a moulded sandstone surround, and a sandstone sill. C. E. B. Brett, writing in 1971, records that this window is said to have come from Bonamargy Friary. On the east face of the return there is a window to the left at first floor level, matching those at the front, and to the right of it a recess of similar size that appears originally to have been a window, retaining its iron security bars. The gable of the return is finished in unpainted cement render, while the west and east faces are of rubble construction with rough alternating sandstone quoins.

Only a narrow section to the far left and a slightly broader section to the right of the main building's rear facade are exposed. Beneath the lean-to extension at the far left there is a small window with what appears to be a sash frame, though it can only be seen from a distance and appears partly obscured by the return of the neighbouring property to the west. To the right on the rear facade of the main section there is a ground-floor doorway with a timber-sheeted door, and a matching window at first floor level. This portion of the facade is largely rubble constructed, with a small section of cement render and some brick dressings to the openings.

The gabled roof of the main section is slated; the covering on the return roof could not be inspected. Rainwater goods are a combination of cast iron and PVCu. To the rear of the building is a relatively small open yard enclosed by a wall that is part rubble, part brick, and part rendered. In the south-east corner of the yard is a small single-storey shed with red brick walls — with small sections in concrete block and render — and a slated gabled roof. Its north gable has a timber-sheeted door and a window with a timber sash frame.

The building is recorded as Ballycastle's market house, with a gaol within the return, in the valuation of 1835. The Ordnance Survey Memoirs of the same year describe it as a plain two-storey building, with the lower part used as a kind of shambles or market place and the room above used for holding manor courts and petty sessions. The gaol or bridewell at the rear comprised two underground cells and two above ground, used chiefly for confining riotous persons and formerly for confining debtors in connection with the manor court. Samuel Lewis, writing in 1837, refers to the building as a very good market house and commodious court house.

The age of the building is not certain. C. E. B. Brett, writing in 1973, dated it to around 1830, but the valuers of 1835 considered it considerably older — their grading indicated they believed it to be at least 25 to 30 years old at that time. Given that Castle Street appears to have been largely built in the mid-18th century, probably the 1740s, the building is likely to date from around that period. Its relative plainness and lack of formal pretension, which might almost be described as vernacular in character, also points more naturally to an 18th century rather than a mid-19th century date. By 1859 the lower storey had ceased to function as a market house and was rented to a grocer named Andrew Sharpe, listed as such in Slater's 1856 Directory. The ground floor continued to be rented out until the 1920s, by which time the originally open arches had been filled in with the present doors and window. In 1929 Ballycastle Urban District Council took over the whole building and, according to valuation records, used the ground floor as stores. The first floor room is believed to have served as a courtroom as late as the 1980s, and is also understood to have been used at various times as a public library and a credit union office. At the time of recording, the ground floor housed the town museum, with the upper floor largely disused.