Nico Ditch is a six mile (9.7 km) long linear earthwork between Ashton-under-Lyne and Stretford in Greater Manchester, England. It was dug as a defensive fortification, or possibly a boundary marker, between the 5th and 11th centuries.
The ditch is still visible in short sections, such as a 330-yard stretch in Denton Golf Course. In the parts which survive, the ditch is 4–5 yards wide and up to 5 feet deep. Part of the earthwork is protected as a Scheduled Ancient Monument.
Nico Ditch stretches six miles (9.7 km) from Ashton Moss (grid reference SJ909980) in Ashton-under-Lyne to Hough Moss (grid reference SJ82819491), just east of Stretford. It passes through Denton, Reddish, Gorton, Levenshulme, Burnage, Rusholme, Platt Fields Park in Fallowfield, Withington and Chorlton-cum-Hardy, crossing four metropolitan boroughs of present-day Greater Manchester. The ditch coincides with the boundaries between the boroughs of and Manchester, and between Tameside and Manchester as far as Denton golf course. A section is now beneath the Audenshaw Reservoirs, which were built towards the end of the 19th century. The ditch may have extended west beyond Stretford, to Urmston (grid reference SJ78299504).