The Tavistock Canal was constructed early in the 19th century to link the town of Tavistock to Morwellham Quay on the River Tamar on the Devon and Cornwall border, where cargo could be loaded into ships. Outbound cargo included ore from local mines and mineral lodes were explored and exploited during the construction of Morwell Down Tunnel.
Though closed to navigation by around 1880 the canal has found a second life supplying water to Morwellham Hydro Electric Power Station and forms part of the Cornwall and West Devon Mining Landscape World Heritage Site.
The main line of the canal starts at the Abbey Weir in Tavistock, where water is taken from the River Tavy. Passing through wharfs in Tavistock, it proceeds towards Morwellham Quay in a fairly straight line, with a large horseshoe loop when it meets the valley of the River Lumburn, which it crosses by a large aqueduct.
The two-mile Mill Hill branch turned off immediately after the aqueduct.
After about 3 miles (4.8 km) the main line reaches the northern portal of the Morwell Down tunnel, which emerges 1.5 miles (2.4 km) later above the quay.
A short length of canal after the tunnel brought boats to the top of the inclined plane which provided a link down to the Port of Morwellham.