The Monmouthshire Canal was granted its Act in 1792 and by 1796 eleven miles from Pontnewynydd to Newport were complete. The eleven mile Crumlin Arm from Crindau Junction to Crumlin was fully open by 1799. The canal was built to carry coal and iron to Newport and it led to a rapid expansion of the town and the riverside wharfs.
Tramroads were feeders to the Canal from the more mountainous areas such as Blaenafon but became direct routes to Newport in the Western Valley. Tramroads gradually became more important than the Canal and by 1848 the Company had become the Monmouthshire Railway and Canal Company. It bought out the Brecknock and Abergavenny Canal in 1865 and by the time the GWR took over the day-to-day running in 1 875 the Canal was of little commercial importance except for the supply of water to Newport Docks.