The River Dock is one of three river locks on the Tennant Canal and the masonry indicates that it was built as part of the Neath Harbour Scheme. There is a large rectangular dock basin at canal level (adjacent to the river lock, NPRN 34544), and the remains of timber loading stages project into the river. The River Neath navigation was the longest in the south Wales coalfield. The connection between the River Neath and the Tennant Canal was originally done at Red Jacket and Neath. A proposal to transform a mile long tidal section of the river into one of the largest enclosed or 'floating' dock schemes in south Wales necessitated a third lock and adjacent transhipment dock basin at Skewen. A site survey was carried-out in May 1977 by David Leighton, Brian Malaws & Stephen Hughes of the RCAHMW.

Sources:
Stephen Hughes & Paul Reynolds, 'A Guide to the Industrial Archaeology of the Swansea Region' (Aberystwyth & Swansea, 2nd. ed., 1989)