Colorado River State Park is located in the Plateau Province and features a 20-mile long reach of the Colorado River between Island Acres and Loma. This park currently includes four reaches of the river: Island Acres, Corn Lake, Thirty Road and Connected Lakes. The Colorado River has cut through Cretaceous sandstone and shale formations in the upper one-third of the corridor; those exposed at Island Acres include Mancos shale and the Mesa Verde group, sandstone and coal layers of the Mount Garfield, Sego Sandstone and Hunter Canyon Formations. Tertiary sandstone, siltstone and shales of the Wasatch and Ohio Creek formations are exposed along the Book Cliffs. Landslides are common in this area, leaving debris below cliffs which is eroded, carried down-river and redeposited across the floodplain. Pleistocene and Holocene alluvial deposits can be seen throughout the length of the park; these consist of silt, sand and gravel eroded from parent material along the river course and deposited in the floodplain and on adjacent fans and low terraces.

Ecologically, park uplands support desert shrublands dominated by big sagebrush, four-wing saltbush, shadscale and greasewood. These communities occur in relatively pure stands in some areas and as mixed stands over much of the corridor. Big sagebrush communities are best represented on the eastern end of the corridor, occupying high terraces along the river. Saline bottomland shrublands featuring greasewood and four-wing saltbush occur near 30 Road, while salt desert shrub communities dominated by shadscale occur throughout the entire corridor. Commonly associated species include rabbitbrush, squirreltail, galleta, western wheatgrass, Indian ricegrass, alkali sacaton and saltgrass. Much of the landscape along the river has been altered to support agricultural crops, including fruit orchards, and urban landscaping and flood control projects. Diverse wetland and riparian communities occur within and along the river corridor, on islands, point bars, ground water seeps, gravel pit margins and constructed sites used for mitigation to offset development-related impacts.

Many migratory and resident birds are known for this area including several species of raptors, lark and vesper sparrows, horned lark, western meadowlark, black-billed magpie and waterfowl and shorebirds. Mule deer are very common and elk, black bear and mountain lion are less common large mammals that may be observed. The cottontail rabbit, coyote, red and gray fox, raccoon, beaver, prairie dog and ground squirrel are commonly seen along the corridor. Many anglers are attracted by the warm- and cold-water fishing opportunities, which include channel catfish, bluegill, smallmouth bass, black bullhead, a sunfish/bluegill hybrid, carp and rainbow trout. Four fish species listed as threatened or endangered could also be present in the Colorado River.