Petrified Forest National Park, desert area containing plant and animal fossils and archaeological sites in eastern Arizona, U.S., 19 miles (30 km) east of Holbrook. It was established as a national monument in 1906 and as a national park in 1962. The area within the park proper is 146 square miles (378 square km), but, since 2005, additional land parcels have been acquired and placed under park administration, so that the entire protected area now totals 346 square miles (896 square km).

The park consists of two unequal-size areas, north and south, joined by a narrow neck of land near the park’s north entrance. The southern portion, the larger of the two, includes extensive areas east and west of the park proper that are now administered by the park but that are still privately owned. The northern lobe of the park lies largely within the southeastern extension of the Painted Desert, a badlands region of colourful wind-eroded hills. Pilot Rock (6,235 feet [1,900 metres]), in the northwestern corner of the northern lobe, is the park’s highest point. Much of the northern lobe is designated as a wilderness area.

The park features extensive exhibits of petrified wood in several “forest” areas, which are the remains of ancient tropical groves. Of note is the Black Forest Bed in the park’s northern portion. Other sections of the park (Blue Mesa and Jasper, Crystal, and Rainbow forests) are filled mostly with fossilized leaves, plants, and broken logs. Some animal fossils also have been found, including those of dinosaurs and phytosaurs that date to the Triᴀssic Period (252 to 201 million years ago). Among the park’s archaeological features are petroglyphs (e.g., Newspaper Rock) and the ruins of ancient Ancestral Pueblo (Anasazi) pueblos, notably the Puerco Indian Ruin just south of the Painted Desert. Other attractions include the Painted Desert Inn National Historic Landmark near the north entrance and the Rainbow Forest Museum near the south entrance.

The park’s elevation, which averages about 5,800 feet (1,800 metres), and its annual precipitation, which is less than 10 inches (250 mm), are the primary factors in determining the type of plant and animal life. Many of the plants are small and inconspicuous, but some plants blossom in the spring—yuccas, mariposa lilies, and cacti—and others provide summer flowers—asters, rabbit brush, and sunflowers. Wildlife includes coyotes, bobcats, antelope, rattlesnakes, lizards, and a variety of birds, notably the horned lark, rock wren, and phoebe.

The park is accessible by road at its north and south entrances; the road serving the north entrance follows the historic Route 66 highway. A north-south road through the southern portion of the park connects the two entrances. The park has dining and retail facilities but no overnight lodging accommodations or developed campgrounds. Backcountry camping is permitted in designated wilderness areas.