Swan Lane Mills is a former cotton mill complex in Bolton, Greater Manchester, England.^[1] All three mills are Grade II* listed buildings.^[2] The mills were designed by Stott and Sons of Oldham. When completed, the double mill (Nos. 1 and 2) was the largest spinning mill in the world. It was granted Grade II* listed status on 26 April 1974.^[3] Number 3 Mill was separately listed as Grade II* on the same day.^[4]

Swan Lane Mills are typical of the final phase of cotton mill construction in Lancashire, of vast size and decorated with flamboyant terracotta embellishments reflecting the industry's prominence and prosperity.^[5] The mill was planned as a double mill with a central boiler house and built in two phases.^[6] Swan Lane Number 1 Mill was built in 1902, and Number 2 Mill three years later. The double mill was built to contain 210,000 mule spindles.^[7] Number 3 Mill was built in 1915^[8] and housed 120,000 mule spindles. Number 1 Mill spun fine counts using Sea Island Cotton and Number 2 Mill concentrated on medium counts using Egyptian cotton.^[9]The mill also had 250 carding and 200 drawing and roving frames.^[10]

The mills are constructed in brick with yellow brick decoration.^[10] Both mills are of five storeys over a basement and were built in the same style with wide segmentally arched windows and flat concrete roofs. They have a yellow brick eaves band and a stone dentilled cornice. Their projecting stair towers have Italianate details and balustraded parapets. The double engine house on the north-west side was built to power both mills. The rope race tower projects behind it. The mill chimney has been reduced in height but retains an emblem of a swan in white lettering. Its internal construction is of cast iron columns and brick arched ceilings.^[3] No.1 Mill is 25 bays wide and five deep with a single storey and basement extension to its north side, possibly a card room, but now used as a warehouse. No.2 Mill is 23 bays long and six deep. The mill's two-storey office block is attached next to the site entrance.^[3]

No. 3 Mill of 1915 is brick built with stone dressings, rounded corners and a ridged slate roof. It is 23 bays long, 14 wide with segmentally headed windows and eight storeys high (six plus a double attic).^[4] It is possibly the tallest of the mule-spinning mills most of which were up to six storeys in height.^[8] Above the sixth storey is a cornice from where carved swans project at intervals and the arcaded attic has round windows to its upper storey. The south-west corner entrance has a panel with a carved swan above the doorway and accesses a staircase. The tower above it is corbelled above the fifth floor and has angle pinnacles. A two-storey extension houses the card room and warehouse. Its engine house, two bays wide and three deep, has round arched windows.^[4]

George Saxon & Co supplied No. 1 Mill with a cross compound engine (works number 352) in 1903. It developed 1300hp, had 26 and 52 inch cylinders with a 5-foot stroke and its 26-foot flywheel powered the machinery via 35 ropes. In 1906 an identical engine was installed for No. 2 Mill. No. 3 Mill was powered by a 2000 hp vertical triple expansion engine also supplied by Saxons. It had a 25 feet diameter flywheel weighing 25 tons, Corliss valves and 44 ropes. Steam was generated by ten Lancashire boilers. The engines powered the entire mill complex until 1959 when motor-driven ring frames were installed but one engine continued to provide power for some processes in Nos. 1 and 2 Mills.^[11]

In 1983, Swan Lane Mills was featured in an episode of the documentary Fred, in which Fred Dibnah is hired to remove the decorative ornamental on top of the chimney^[12] by then the last decorative topped chimney in Bolton.^[13] He was paid £4,000 (1982) for the work.

• Grade II* listed buildings in Greater Manchester
• Listed buildings in Bolton
• List of mills in Bolton