Lanark (lănˈərk, –ärk) [key], town (1991 pop. 9,778), South Lanarkshire, S central Scotland, on the Clyde River. It has cattle markets and textile mills. There are hydroelectric power stations at the Falls of Clyde, just S of Lanark. Sir William Wallace's first act of rebellion (1297) was the murder of the English sheriff of Lanark and the burning of the town. Robert Owen conducted industrial and social experiments at the nearby New Lanark mills, founded by his father-in-law, David Dale, in 1785.