Heads at 630238N, 1612638W, flows SW to Yukon River, 25 mi. W of Marshall, Yukon-Kuskokwim Delta. 165 miles long.
Eskimo name first appearing as "Chuilanuk" on a fieldsheet by R. H. Sargent, U.S. Geological Survey (USGS), dated 1916. Sargent notes that it is the "lower end of 5 day Sl(ough). It takes 5 days to row through this slough because it is so sinuous." The spelling has been modified to "Atchuelinguk" on recent maps to conform more closely with pronunciation. It refers in meaning to "water that isn't roily."