Polson Bridge is about a mile and a half east of Launceston on the River Tamar. The town’s castle is seen on the skyline to west on the left. The rather makeshift-looking bridge here has since been replaced but the original structure is shown clearly in Joseph Farington’s 1813 engraving Poulton Bridge and Launceston (impression: Government Art Collection, London). Turner recorded the same view in more detail in the contemporary Devonshire Rivers, No. 3, and Wharfedale sketchbook (Tate D09826; Turner Bequest CXXXIV 34), and also a view of the other side of the bridge, looking eastwards up the valley (Tate D09825; Turner Bequest CXXXIV 33).
The bridge is mentioned in a note in the Devon Rivers, No.2 sketchbook (Tate D09732; Turner Bequest CXXXIII 51a).