The River Irt is a river in the county of Cumbria in northern England. It flows for approximately 22 kilometres (14 mi) from its source in Wast Water to its estuary at Ravenglass.
The name of the river is believed to derive either from the Old English gyr which means "mud",[1] or from the Brittonic words *ar, "flowing",[2] or *īr, "fresh, clean, pure",[2] suffixed with -ed, a nominal suffix meaning "having the quality of...".[2]