Old Parish Church, Tarbolton

The Old Parish Church at Tarbolton was built in 1821 by Robert Johnston. It is a near rectangular-plan, classical church with a dominant steeple, set within a formal landscape.

The church is a five-bay, two-storey structure with a base course, eaves course, cornice, pilaster quoins, and dies rising through the roofline. A shallow blocking course is also present. The square-plan tower has moulding to its base, and an eaves course, cornice and blocking course to its pilastered first stage; scrolls decorate the pilaster strips at the second stage, with roundels at the apex.

The northeast (entrance) elevation features steps leading to an advanced three-bay central entrance. It has three square-headed entrances: a larger central entrance with a block-pedimented consoled cornice and a two-leaf timber door, flanked by two smaller entrances, also with two-leaf timber doors. Decorative letterbox fanlights are above each entrance, the central one being larger. A string course runs above the ground floor and is punctuated by a Venetian window flanked by single windows. Above the main block, the tower rises and includes a single window at the first stage, a clock face at the second, a polygonal-plan louvred belfry above that, and a final weather finial. The recessed flanking bays have single windows at both ground and first floor levels, with consoled cornices to ground floor openings and pedimented first floor openings.

The southwest (rear) elevation has two large arched windows to the centre, and an off-centre small window flanked by two larger single windows within a lean-to section. The southeast (side) elevation features the tower to the right, rising above the first floor as it does on the northeast elevation; the first stage of the tower is blind. Four segmental arched windows are at ground floor level (one infilled), with four round-arched windows above. A timber door is set into the recessed lean-to on the outer left.

The northwest (side) elevation repeats the tower to the left, again rising above the first floor. It has four segmental arched windows at ground floor level (one infilled), with four round-arched windows above, and a lean-to to the outer right. The windows are mainly small-paned timber sash and case designs, and the roof is slate.

The interior includes a tiled entrance porch floor and a rope rail to the left-hand gallery staircase. Timber handrails are on the right. Curved upper timber galleries feature unusual rustic arm-rests, and are beneath a modillion cornice. The church contains timber box pews, panelling to the galleries (supported by timber columns), a central timber pulpit, altar furniture, and a timber pedimented screen to the organ.