The lock adjoins a small thin island created in its building accessible by boat that connects Chertsey Weir.

Upstream lay shallows known to ground boats, Laleham Gulls; to resolve this, proposals including the building up of banks, a weir and lock were made.

A proposal was authorised by Parliament in 1810 a short way upstream which Lord Lucan, owner of the manor of Laleham, asked to have modified to be out of view of his home which he expended monies in building and redesigning, hosting in the same era the temporarily ousted Portuguese monarch, Laleham Manor House (later apartments in a listed building).

Below Penton Hook Marina at the top of the reach adjoining houses and small boatyards is the offtake of the Abbey River enclosing Laleham Burway, Chertsey a very large island on the right bank which rejoins the Thames below Chertsey Lock; has housing in the north then areas of reeds and nettles; inland are a small reservoir and groundwater water works.

An inlet along the upper left bank feeds around 200 million imperial gallons (910,000 m3) per day of water into the Queen Mary Reservoir.