[6] The old mining camp of Swansea (now a ghost town) lies in the Buckskin Mountains about 3.7 miles (6.0 km) south of the river.

[9] Fish species in the Bill Williams river include largemouth bass, yellow bullhead, green sunfish, bluegill, carp, mosquitofish, red shiner, razorback sucker, and others.

The lowland leopard frog, North American river otter, beaver, muskrat, Arizona toad, and spiny-spotted turtle are among the major aquatic vertebrates found in or near the water.

[11] The Sonoran Desert rare riparian habitat of Bill Williams River NWR draws a variety of Neotropical migratory birds, from Central and South America en route to their breeding grounds in the north.

It has one of the last stands of the natural Cottonwood-Willow Forests plant community along the lower Colorado River, with Fremont's cottonwood (Populus fremontii) and Goodding's willow (Salix gooddingii) the primary tree species.