The lock was built in 1896 by the Thames Conservancy to replace a flash lock at Hart's Weir, also known as Ridge's Weir, about a mile upstream and another at Ark Weir downstream. The lock house, lock and weir are relatively little changed since they were built and they can be viewed as a group from the Thames Path and from the river.
The weir is just the other side of the lock island and is one of only two remaining complete paddle-and-rhymer (or rimer) manually operated weirs. It is thought that there are no other such weirs in the world.
Access to the lock
The lock is remote from the village of Northmoor and some distance walk across country. The weir can be reached from Appleton, which is an equal distance away on the Berkshire bank. It can also be reached by the Thames Path from Bablock Hythe and Newbridge.
Reach above the lock
The Thames Path follows the Oxfordshire bank to Newbridge, and then crosses over and continues on the Berkshire bank to Shifford. There it crosses again, over the old course of the river, to Shifford Lock, then across the lock towards Chimney Meadows.