Deerpark Bridge, Antrim Castle Gardens, Randalstown Road, Antrim, Co Antrim

Deerpark Bridge is a rubble stone bridge likely dating to the early 18th century. It carries an estate road over the Six Mile Water, running approximately north-east to south-west. The bridge is of six segmental arches built with rough stone voussoirs on both faces. Salient angle piers rise in two places to form projecting pedestrian refuges at parapet level on both faces, with slightly projecting parapets. The soffits of the vaults are of random rubble. The carriageway surface is a humped combination of tarmac and compacted gravel. Parapets extend to angled approach walls; the southern approach wall on the north-east side is supported by three buttresses and terminates in a low segmental arched recess.

The bridge is situated within the former demesne of Antrim Castle, connecting the Castle Gardens to the north-east with the former deerpark to the south-west, now occupied by sports pitches. Grass banks border the bridge on either side, alongside mature trees. A gateway closes the carriageway at the south-west end, consisting of a pair of square ashlar stone piers with moulded plinths, fluted friezes, moulded cornices, and plain blocking courses. Both piers are damaged, with portions of the upper sections broken. The piers are topped with original iron vehicular gates featuring spear-head railings, flanked by smaller pedestrian gates of similar design.

The precise construction date is unrecorded, but the bridge appears on the Ordnance Survey map of 1832. Built by one of the Viscounts Massereene as a private bridge to provide access between the castle gardens and the parkland, its style suggests a possible date around 1708, based on similarities to nearby Massereene Bridge. In the 1830s, it was described as "an old, but strong bridge." The listing includes the bridge itself, along with the gates and gate piers. The bridge is located within a conservation area.