Theodore Roosevelt created Petrified Forest National Monument on December 8, 1906. Petrified Forest was designated as a national park on December 9, 1962.
The park boundary encloses 221,390 acres, with legislation in 2004 more than doubling the authorized size of the park.
The park has over 50,000 acres are designated The Petrified Forest National Wilderness Area (1970), one unit at the north and another at the south end of the park.
While sometimes called a high desert, the main environment of the park is Intermountain Basin semi-arid steppe and grassland (shortgrass prairie).
Hundreds of species of plants and animals can be found in the park, including elk, mule deer, pronghorn, bobcat, coyote, kitfox, badger, prairie dog, porcupine, rodents of many kinds, black-tailed jackrabbit, various bats, raven, golden eagle, red-tailed hawk, burrowing owl, horned lark, scaled quail, many songbirds, hummingbirds, roadrunner, collared lizard, bullsnake, short-horned lizard, Hopi rattlesnake, side-splotch lizard, whiptail lizard, kingsnake, spadefoot toad, tiger salamander, tarantula, scorpion, many butterflies and moths, solitary bees, tarantula hawks, carpenter ants, triops, hundreds of wildflowers, yucca, cactuses, sagebrush, skunkbush, grasses such as blue grama, juniper, cottonwood, lichen, puffballs, just to name a few.
Over 13,000 years of human history can be found in the park, including over 800 archeological and historic sites.
Puerco Pueblo was built by the ancestral Puebloan people, occupied between A.D. 1200 and 1400. Agate House was occupied about A.D. 1100-1150 and was built out of pieces of petrified wood.
Herbert David Lore built Painted Desert Inn (aka the Stone Tree House) by 1924. Using designs by National Park Service architect Lyle Bennett, the Civilian Conservation Corps (CCC) reconstructed the Painted Desert Inn in the late 1930s. From 2004-2006 the building had an extensive rehabilitation, returning the inn to its 1949 appearance. It was placed on the National Register of Historic Places in 1976 and became a National Historic Landmark in 1987.
Petrified Forest National Park is the only national park site that contains a segment of the Historic Route 66 alignment. Part of the National Old Trails Highway also passed through the park.
Exposed at Petrified Forest is one of the most continuous sections of Triassic-aged rocks anywhere in the world. These rocks were deposited by enormous rivers between 208 and 225 million years ago and include an incredible diversity of fossils. The Chinle Formation of the Triassic Period is the main geologic formation of the park. The Bidahochi Formation outcrops in the north, laid down during the Miocene and Pliocene of the Quaternary Period, about 3-8 million years ago.
When the trees died, they washed into an ancient river system and formed log jams, buried sediment. Minerals, including silica dissolved from volcanic ash, absorbed into the porous wood over hundreds and thousands of years crystallized within the cellular structure, replacing the organic material as it broke down over time. If there were larger spaces such as a hollow or crack in the logs, crystals of clear quartz, purple amethyst, yellow citrine, and smoky quartz formed.
The brilliant colors in the petrified wood come mainly from trace minerals. Pure quartz is white, manganese oxides form blue, purple, black, and brown, and iron oxides provide hues from yellow through red to brown and black.
Annual visitation to the park is about 800,000 people. You can visit the Public Use Statistics Office website for all park visitation statistics.