[3] It flows southeastwards to the Kwiniuk Inlet at the northwestern end of Norton Bay, 25 miles (40 km) southwest of Koyuk in the Bering Sea.

Exploration for placer gold occurred in the Council district area where the river valley is located, and in 1898, mining commenced.

After the flats, there is a more restricted valley with the high hills of the Cape Darby granite area to the west and the softer forms of the limestone and schist on the east.

Above the canyon, the stream valley broadens out again into a basin of a smaller area but otherwise similar to that of Fish River and is connected with the latter by a low pass used in winter in making the overland trip from Golovnin Bay to Kotzebue Sound.

It rises in a group of granite mountains south of the source of the Koyuk, flows out into a small basin quite like that of Fish River, though much smaller in area, and enters the hills again at about latitude 65° 10'.

From this point it continues, with many loops and bends and variations in the width of its valley, until it passes into its delta plain, 11–12 miles (18–19 km) above its mouth.

The first two of these are the only streams belonging to the Tubutulik drainage system The lower course of the river lies in a fluvial plain consisting partly of fresh-water and partly of salt-water marshes, built up by the detrital material carried by the river itself and deposited beyond its mouth in the form of mud, sand, and gravel.

The radioactivity recorded in the area was tested and found to be concentrated in the Tubutulik River and its tributaries at many locations.