Bourne Lock, Bridge and Weir Immediately North of Bourne Mills

Bourne Lock, Bridge and Weir, located immediately north of Bourne Mills, is a 19th-century structure made of red brick with ashlar limestone dressings. The bridge spans the tail of the lock and has a roughly rectangular shape. Its wing walls curve gently outward and are battered, terminating in pilasters. The arched opening is segmental and nearly semi-circular, featuring ashlar springers and a plain curved string along the top. The parapet is simple, with plain stone copings on both it and the flank walls.

The lock itself has brick walls that widen at the entrance on the south end, with large stone copings and ashlar dressings at the gate positions, where iron fittings are attached to the gateposts. One original lock-gate is still partially intact. The structure includes double gate recesses, and an arch at the top of the chamber indicates its historical evolution, showing where the lock was shortened to conserve water.

Adjacent to the lock is the by-weir, which is part of the site's water management system. This rectangular structure is partly built of stone but was heavily overgrown at the time of inspection in 2009.