The Tennant Canal was a development of the Glan-y-wern Canal, which was built across Crymlyn Bog to transport coal from a colliery on its northern edge to a creek on the River Neath called Red Jacket Pill. It closed after 20 years, but was enlarged and extended by George Tennant in 1818, to provide a navigable link from the River Neath to the River Tawe at Swansea docks. In order to increase trade, he built an extension to Aberdulais basin, where it linked to the Neath Canal. The extension was built without an act of Parliament and there was a long delay while Tennant attempted to resolve a dispute with a landowner over the routing of the canal. Once opened, much of the Neath traffic used the Tennant Canal, as Swansea provided better facilities for transferring cargo to ships.