The Foss Dyke, or Fossdyke, connects the River Trent at Torksey to Lincoln, the county town of Lincolnshire, and may be the oldest canal in England that is still in use. It is usually thought to have been built around 120 AD by the Romans, but there is no consensus among authors. It was refurbished in 1121, during the reign of King Henry I, and responsibility for its maintenance was transferred to the city of Lincoln by King James I. Improvements made in 1671 included a navigable sluice or lock at Torksey, and warehousing and wharves were built at Brayford Pool in the centre of Lincoln.
Connection to The River Witham at Brayford was hampered by the small bore and depth of High Bridge, a medieval structure just below the pool. The channel through it was made deeper in 1795, but John Rennie's plans to demolish it in 1803 were not adopted. The canal was leased to several generations of the Ellison family, who profited from the tolls but failed to maintain it. Although cargos of coal and wool moved to the railway, the carriage of grain continued, and the last commercial operation was in 1972. The Brayford Mere Trust have turned Brayford Pool from a rubbish-filled eyesore into an attractive marina, and the Lincolnshire Waterways Partnership are opening a footpath and cycleway from Lincoln to Torksey; the section to Saxilby was officially opened on 26 July 2011.
The Fossdyke joins the River Trent at Torksey. A branch leaves the main channel, passes under the A156 bridge, and immediately enters Torksey lock, which is the only lock on the canal. It has six sets of gates, three sets facing Lincoln, and three facing the river, which is tidal at this point, and so its level can be higher than the level of the canal. The gates allow the lock to be used at most states of the tide. A steel footbridge crosses the lock near the road, and both the footbridge and the lock are grade II listed structures. The canal runs to the east, and then turns south, passing to the east of Fenton and Kettlethorpe. Soon it is joined by the A57 road, and turns east again. The road runs along the south bank, until Saxilby is reached.