The geologic history of the park is related to that of nearby Grand Canyon and Zion (Zion National Park) national parks, since the foundation stone of all three was laid down while the entire region was inundated by a shallow sea; the sandstone and limestone beds of Bryce Canyon, however, were formed more recently, during the past 60 million years (the Cenozoic Era). Some 13 million years ago the land began to rise slowly, and plateaus, or tablelands, rising as much as 2,000 feet (610 metres) above the surrounding countryside, were created along fault lines. From the eastern edge of the Paunsaugunt Plateau, erosion, caused largely by the freezing and thawing of water in the cracks of the rocks, carved a series of horseshoe-shaped amphitheatres. Within 12 of these amphitheatres and below the rim of the plateau are the colourful formations for which the park is noted, made mostly of limestone layered with sandstone; these structures include pinnacles, windowed walls, mazes, spires, cathedrals, recesses, and fins. Hiking and horseback riding trails that descend some 500 feet (150 metres) below the plateau's rim allow visitors access to the rock formations.

The high-rim country of the park is part forest and part grass and sagebrush, with fir, pine, and aspen the dominant species of trees. At lower, drier elevations, piñon pine and Utah juniper predominate. The park harbours many mammals, including deer, porcupines, and chipmunks; prairie dogs, which had been eradicated from the park by the 1950s, were reestablished in the 1970s. Among the many bird species found in the area are woodpeckers, Steller's jay, the blue grouse, and ravens.