The Mersey and Irwell Navigation was a river navigation in North West England, which provided a navigable route from the Mersey estuary to Salford and Manchester, by improving the course of the River Irwell and the River Mersey. Eight locks were constructed between 1724 and 1734, and the rivers were improved by the construction of new cuts several times subsequently. Use of the navigation declined from the 1870s, and it was ultimately superseded by the Manchester Ship Canal, the construction of which destroyed most of the Irwell section of the navigation and the long cut between Latchford and Runcorn.
