The Sheffield, Ashton-under-Lyne and Manchester Railway was an early British railway company which opened in stages between 1841 and 1845 between Sheffield and Manchester via Ashton-under-Lyne. The Peak District formed a formidable barrier, and the line's engineer constructed Woodhead Tunnel, over three miles (4.8 km) long. The company amalgamated with the Sheffield and Lincolnshire Junction Railway and Great Grimsby and Sheffield Junction Railway companies, together forming the Manchester, Sheffield and Lincolnshire Railway in 1847.

Ashton-under-Lyne is a market town in Tameside, Greater Manchester, England. The population was 48,604 at the 2021 census. Historically in Lancashire, it is on the north bank of the River Tame, in the foothills of the Pennines, 6 miles (9.7 km) east of Manchester.