Blackburn ( (listen)) is an industrial town and the administrative centre of the Blackburn with Darwen borough in Lancashire, England. The town is north of the West Pennine Moors on the southern edge of the Ribble Valley, 8 mi (13 km) east of Preston and 21 mi (34 km) north-northwest of Manchester. Blackburn is the core centre of the wider unitary authority area along with the town of Darwen. It is one of the largest districts in Lancashire, with commuter links to neighbouring cities of Manchester, Salford, Preston, Lancaster, Liverpool, Bradford and Leeds.

At the 2011 census, Blackburn had a population of 117,963, whilst the wider borough of Blackburn with Darwen had a population of 150,030. Blackburn had a population of 117,963 in 2011, with 30.8% being people of ethnic backgrounds other than white British.

A former mill town, textiles have been produced in Blackburn since the middle of the 13th century, when wool was woven in people's houses in the domestic system. Flemish weavers who settled in the area in the 14th century helped to develop the woollen cottage industry. The most rapid period of growth and development in Blackburn's history coincided with the industrialisation and expansion of textile manufacturing.

Blackburn's textile sector fell into decline from the mid-20th century and subsequently faced similar challenges to other post-industrial northern towns, including deindustrialisation, economic deprivation and housing problems. Blackburn has had significant investment and redevelopment since 1958 through government funding and the European Regional Development Fund.