Farnworth is a town and an unparished area within the Metropolitan Borough of Bolton in Greater Manchester, England. It is located 2.3 miles (3.7 km) southeast of Bolton, 4.3 miles south-west of Bury (7 km), and 7.5 miles (12.1 km) northwest of Manchester.
Historically in Lancashire, Farnworth lies upon the River Irwell and the River Croal. According to the United Kingdom Census 2001, it had a population of 25,264 people. It was increased to 30,271 at the United Kingdom Census 2011, by combining the population figures of the Farnworth ward (15,793), which covers the eastern half of the town, and the Harper Green ward (14,478), which covers the west side.