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 during the 14th century helped to develop the woollen cottage industry. James Hargreaves, inventor of the spinning jenny, was a weaver in Oswaldtwistle near Blackburn and the most rapid period of growth and development in Blackburn's history coincided with the industrialisation and expansion of textile manufacturing. Blackburn was a boomtown of the Industrial Revolution and amongst the first industrialised towns in the world.
Blackburn's textile sector fell into terminal decline from the mid-20th century and subsequently faced similar challenges to other post-industrial northern towns, including deindustrialisation, economic deprivation and housing issues. In recent decades, the town has experienced significant levels of migration, with people of ethnic backgrounds other than white British making up 30.8% of the population, above the regional and national average. Blackburn has had significant investment and redevelopment since 1958 through government funding and the European Regional Development Fund.
Blackburn was recorded in the Domesday Book as Blacheborne in 1086. The origins of the name are uncertain. It has been suggested that it may be a combination of an Old English word for bleach, together with a form of the word "burn", meaning stream, and may be associated with a bleaching process. Alternatively, the name of the town may simply mean "black burn", or "black stream".
There is little evidence of prehistoric settlement in the Blakewater valley, in which Blackburn developed. Evidence of activity in the form of two urn burials has been discovered from the Bronze Age in the hills around Blackburn. In 1879, a cinerary urn was discovered at a tumulus at Revidge, north of the town; another was excavated in 1996 at Pleasington Cemetery, west of the town, by gravedigger Grant Higson. The presence of a sacred spring—perhaps in use during the Iron Age—provides evidence of prehistoric activity in the town centre, at All Hallows Spring on Railway Road.
Blackburn is located where a Roman military road crossed the river Blakewater. The road linked Bremetennacum Veteranorum (Ribchester) and Mamucium (a major Roman fort that occupied Castlefield in Manchester). The route of the road passed east of Blackburn Cathedral and probably crossed the river in the Salford neighbourhood just east of the modern town centre. It is not clear whether the road predated the settlement.