The Guadalupe River, with banks lined by huge bald cypress trees, is the park's most outstanding natural feature. On its winding path through the park, the river courses over four natural rapids; two steep limestone bluffs reflect its awesome erosive power. Trees in lower elevations and bottomlands include sycamore, elm, basswood, pecan, walnut, persimmon, willow and hackberry. In the uplands away from the river, the limestone terrain is typical of the Edwards Plateau and is composed of oak and juniper woodlands, with interspersed grasslands.
One area of virgin Ashe juniper woodlands provides the proper nesting habitat for the rare golden-cheeked warbler. In addition to numerous species of birds, the park supports a wide variety of wild animals, including the white-tailed deer, coyote, gray fox, skunk, raccoon, opossum, bobcat and armadillo. Other smaller species abound, and efforts of wildlife observers are usually well rewarded.