It lies entirely below 150 feet (45 metres), on the moors of Axe Edge, near the River Dane and the Cat and Fiddle Inn. The Buxton to Macclesfield road crosses the river at Derbyshire Bridge, which was the old boundary between Derbyshire and Cheshire.
The river then reaches an old packhorse bridge which was moved when Errwood reservoir was built in the 1960s.
The first Act of Parliament to canalise a river was obtained by the City of Canterbury in 1515 to extend navigation on the river Great Stour, followed by another Act of Parliament for the river Exe in 1539, which led to the construction in 1566 of a new channel, the Exeter Canal.
The historic market and industrial town of Warrington stands on the border of modern day Lancashire and Cheshire.
From Stockport, the River Mersey flows near Didsbury, Stretford, Urmston, Flixton, and then at Irlam it flows into the Manchester Ship Canal, which canalised the River Irwell to this point.
The course of the Mersey has been obliterated by the Manchester Ship Canal past Hollins Green to Rixton, although the old river bed can be seen at Warburton (see a photo in the Manchester Ship Canal section in Part 2).
The Greater Manchester borough of Tameside is named after it.