St Mary's Island Lighthouse, Keepers' Cottages and Compound Walls

St Mary's Island Lighthouse, Keepers' Cottages, and Compound Walls is a late 18th-century lighthouse complex prominently situated on the eastern side of the island. The lighthouse itself is a white-painted brick tower with a metal roof, standing 126 feet tall. It has scattered window openings, now fitted with timber casement replacements. The lantern room features storm panes with diagonal astragals and hand holds, and a domed metal roof topped with a weather vane. A gallery with a metal balustrade and decorative finials encircles the lamp room; the west side displays the Trinity House Coat of Arms. A modern, covered walkway links the lighthouse to the keepers' cottages. A metal ladder staircase with brass handrails provides access to the lantern room, which retains its original wind vents and baffles, and houses a replacement kerosene lantern originally from Withernsea Lighthouse. The lighthouse tower contains a spiral staircase with 137 steps, originally featuring a metal stick baluster handrail, now enclosed with perspex and a raised safety rail. The upper service room is accessed via a four-panelled door and contains a large wooden and glazed cabinet with a curved front. The keepers' cottages are substantial two-storey buildings constructed from Heworth sandstone with slate roofs, now painted white. They have quoins and four brick chimney stacks. The west and east elevations each have four windows to the ground floor and four to the first floor, with the left end of the west elevation blocked. Modern casements have replaced the original windows and doors. A single-storey, flat-roofed bay with a single window is attached to the south gable end of one cottage. The cottages have been converted into a visitor centre, resulting in the loss of the original two-dwelling layout and most original features. Surviving original features include most architraves, one fireplace opening in the eastern cottage, and a simple stick baluster staircase in the western cottage. The complex is enclosed within stone-walled compound, with walls encompassing the north, east, and south sides of the island.