The last of the major canals of south Wales, Swansea Canal was incorporated
in 1794 and fully opened in 1798. It was basically a speculative
undertaking designed to open up the coal trade at the head of the
valley. It was bought by the GWR in 1873 and worked by them as a
competitor to the Midland Railway's Swansea Vale line. It ceased
to be profitable after 1902 and was closed to all traffic in
1931. Much of the canal has now been filled in or used for road
construction, but it is still in water where it passed through
Clydach and Pontardawe.

(Site entry from "A Guide to the Industrial Archaeology of the Swansea Region", Association for Industrial Archaeology, 2nd Edition, 1989)
B.A.Malaws, 14 November 2003.