Situated on the eastern slope of the Sierra Nevada mountains, the upper end of the valley begins about northeast of Carson Pass, near the confluence where Red Lake Creek flows into the West Fork of the Carson River. From this point, the valley carries the river north for several miles before making a wide turn to the east. About a mile and a half east of the turn, just before reaching Sorensen's Resort, the wide valley abruptly narrows, and a steep V-shaped canyon carries the river further downstream toward the Nevada deserts.