Heads at an unnamed lake, trends S 9 mi then W 26 mi, 2 mi N of Stuyahok Hills, where it trends 10 mi NW to the Mulchatna River at Stuyahok, NE of Dillingham, Bristol Bay Low.
Eskimo name reported as "Estu-y-a-rok" on a 1910 manuscript map by H.C. Fassett, U.S. Bureau of Fisheries (USBF).