Bray Lock is a lock and weir on the River Thames in England near Bray and Dorney Reach, and is just above the M4 Bridge across the Thames. The lock is on the Buckinghamshire side of the river on the opposite bank from Bray itself and Maidenhead which are in Berkshire. Here, the county line stands roughly halfway between the lock and the opposite bank, following the course of the Thames itself. The pound lock was built by the Thames Navigation Commission relatively late in 1845 The lock keeper's cottage is on an island (Parting Eyot) between the lock and the weir.