St. Mary's RC Church, (Dreglish Parish), Drumlegagh Road, Envagh, Castlederg, Co. Tyrone, BT81 7PL

St. Mary's Roman Catholic Church, Drumlegagh Road, Castlederg, is a detached church built in 1846 on the site of an earlier building. It is located on the south side of Drumlegagh Road in the Dreglish Parish.

The church is rectangular in plan with the nave aligned north to south. A single-storey entrance porch was added to the north around 1930, while a sacristy and supporting accommodation were constructed at the south around 1990. The roof is pitched natural slate with blue and black clay ridge tiles, flat stone verges, and replacement cast-metal rainwater goods supported on projecting eaves courses. The walls are rendered in roughcast with droved finished stepped ashlar quoins.

Windows throughout the building are pointed-arched-headed with curvilinear tracery and chamfered mullions, containing stained glass and external secondary glazing. These are set within chamfered droved finish painted surrounds with splayed cills.

The principal elevation faces north and is interrupted at its centre by the single-storey entrance porch, which is detailed as a nave with a shouldered gable and projecting smooth rendered plinth. The exposed section contains three windows, with the outer windows diminished in size. Above the porch, a bellcote at the apex is surmounted by a stone cross finial, with the bell contained in a central round-arched-head opening. The entrance porch contains a replacement off-centre square-headed double-leaf vertically sheeted timber door within a plain smooth rendered surround.

The north gable contains a datestone at its apex reading: "In honour of the Most Holy Trinity / This Temple was built / under the protection of Blessed Mary / Virgin Mother of God / 31st October 1846" (dated MDCCCXLVI).

The west gable contains a central pointed-arched-headed stained glass window with smooth rendered banding and projecting masonry cill. The east elevation is four windows wide and features a mason's mark at the quoin at the north corner.

The south gable is ruled-and-lined rendered and is abutted at its centre by the single-storey sacristy extension, detailed as a nave. The exposed section is blank with a cross finial at the apex. The extension is detailed as a nave with access via a replacement timber glazed door at the right of its east elevation and a timber casement window at the left. The south gable of the extension is blank with a roughcast rendered chimney at the apex. The west elevation of the extension contains a single casement window and has a cat-slide roof.

The west elevation of the main building is four windows wide.

The church sits in a roadside location with a church graveyard to the west containing a range of early nineteenth-century grave markers. The site is bounded to the north by a random rubble wall with segmental coping. Vehicular access is via replacement cast-metal gates supported on random rubble square plan piers with pyramidal capping and ball finials, with a cast-metal overthrow bearing lettering. The church is adjacent to St. Eugene's Hall, located to the north.