The Erewash Valley is the valley of the River Erewash (pronounced /ˈɛrəwɒʃ/ ) on the border of Derbyshire and Nottinghamshire as far as the River Trent. It runs along the boundary of the southern end of the Derbyshire hills and the more rolling Nottinghamshire country. It is on the edge of an area of great mineral wealth, particularly coal, extending from Yorkshire to Leicestershire.