Rochdale, a town of Lancashire, England, on both sides of the river Roch, 10 m. N. N. E. of Manchester; pop. in 1871, 44,559. A parliamentary act in 1872 extended the municipal borough over the district comprised within the limits of the parliamentary borough, making the population of the present limits 63,485. "Within a few years the town has been much improved, the new parts presenting wide, well paved streets, lighted with gas, and lined with buildings of brick and stone. There are more than 20 places of worship and numerous schools, and a fine town hall was built in 1865. The parish church dates from the 12th century. The Roch is here crossed by five bridges. "Woollen manufacture was introduced by Flemish immigrants in the time of Edward III., and the town is now noted for its extensive manufactories of flannel, baize, blankets, and kerseys. There are also cotton warp and yarn mills, calico printing works, hat manufactories, machine shops, and brass and iron founderies. Coal and iron are mined, and slate, flag, and free stones are quarried in the vicinity.

Rochdale is the seat of the most successful of the English cooperative associations, called the equitable pioneers' society; it was founded in 1844 by a few flannel weavers, with a capital of £28 to start a small store for supplying the members with the necessaries of life at cost; at the close of 1870 it had 5,560 members, a share capital of £81,232, several shops and factories, a library of 7,000 volumes, and a sick and burial society, and had largely invested in cottages for members.