The Chesterfield Canal runs between Chesterfield in Derbyshire and West Stockwith (near Gainsborough) in Lincolnshire. There is a description for walkers here. The route is known as 'The Cuckoo Way' after the style of boats on the canal, or perhaps the boatmen. The issue is debated here. The vast majority of the route is on a well-made tow path adjacent to the canal although for around 10km the canal has been infilled and in one area built upon. The current rural nature of Derbyshire, Nottinghamshire and Lincolnshire is reflected in the route's verdant tone in summer. Over a hundred and fifty years ago I imagine that certain stretches would have been very industrial as the canal carried stone, coal and bullets to the River Trent and thus onwards to the rest of the country.
Despite a few flights of locks the route is generally as level as you'd expect a canal to be, with an overall altitude loss of around 60m from Chesterfield to the River Trent. The only exception is at Norwood where the current route must pass over an agricultural mound of around 40m as the tunnel collapsed in 1907.