Incomplete record. Heads at the E end of Davidson Mountains, flows NE across the Alaska-Canada boundary to the Beaufort Sea, SW of Herschel Island in Yukon Canada.
Named by J. H. Turner, U.S. Coast and Geodetic Survey (USC&GS), in 1890, for John Firth, Hudson's Bay Company agent at Rampart house, who accompanied Turner to the Arctic coast that year.