The segment from the point where the river crosses the west limit of T18S, R22E, Kateel River meridian, to its confluence with the Yukon River within the boundaries of the Nowitna National Wildlife Refuge. The river was designated to protect its water quality, wildlife, geology, and primitive setting, and like all wild and scenic rivers, to protect its natural, free-flowing condition. With the exception of the 15-mile canyon area, where peaks up to 21,000 feet border the river, the surrounding terrain is flat, or has low, rolling hills. Numerous lakes and sloughs provide excellent fish and wildlife habitat adjacent to the river.
Riparian vegetation consists of willow, alder, aspen, birch and spruce.
The abundant fish species that utilize the river include sheefish, whitefish, sucker, northern pike, king salmon, chum salmon, burbot, and arctic grayling. The lower portion of the river meanders through one of the most productive waterfowl nesting areas in the state. The Nowitna River is some 200 miles from the nearest road access and population centers. Although the potential for significant impacts to the river exist, for the near future the U.S. Fish and Wildlife Service expects limited increases in public use or other activities such as gold mining that may affect water quality and the integrity of the wild river designation. The Nowitna Wild River is an excellent example of a free flowing interior Alaska river that has seen limited development and which is expected to remain largely unchanged for many years into the future.