The park is only a small portion of a dune field that extends about 200 miles from south of Monahans westward and north into New Mexico. Most of these dunes are stabilized by vegetation, but the park is one area where many dunes are still active. Active dunes grow and change shape in response to seasonal, prevailing winds. At Monahans Sandhills State Park, the visitor will experience a dynamic landscape.

Fresh water occurs at shallow depths within the dune field and sometimes stands in shallow ponds in low areas between dunes. A quiet vigil near such ponds at dusk or dawn is the best way to observe wildlife such as mule deer, gray fox, coyote, bobcat, opossum, wild hog, porcupine, skunk, ground squirrel, jackrabbit and cottontail.

Shin oak (Quercus havardii), one of the plants that stabilize the dunes, is not a stunted or dwarfed form of a larger tree, but a plant that when fully mature usually stands less than 4 feet tall and bears an abundance of large acorns.