Leigh is a town in the Metropolitan Borough of Wigan, Greater Manchester, England, on low-lying land northwest of Chat Moss.

Within the boundaries of the historic county of Lancashire, Leigh was originally the centre of a large ecclesiastical parish covering six vills or townships. When the three townships of Pennington, Westleigh and Bedford merged in 1875 forming the Leigh Local Board District, Leigh became the official name for the town, although it had been applied to the area of Pennington and Westleigh around the parish church for many centuries. The town became an urban district in 1894 when part of Atherton was added. In 1899 Leigh became a municipal borough. The first town hall was built in King Street and replaced by the present building in 1907.

• Population – 41,275
• Metropolitan borough – Wigan
• Metropolitan county – Greater Manchester
• Postcode district – WN7
• Dialling code – 01942

Originally an agricultural area (noted for dairy farming), domestic spinning and weaving led to a considerable silk industry and, in the 20th century, cotton industry. Leigh also exploited the underlying coal measures, particularly after the town was connected to the canals and railways. Leigh had an important engineering base. The legacy of Leigh’s industrial past can be seen in the remaining red brick mills – some of which are listed buildings – although it is now a mainly residential town, with Edwardian and Victorian terraced housing packed around the town centre. Leigh’s present-day economy is based largely on the retail sector.