Petrified wood is a fossil in which the organic remains have been replaced by minerals in the slow process of being replaced with stone. Petrified Forest National Park is a United States national park in Navajo and Apache counties in northeastern Arizona. Old route 66 remnants can still be seen within the park's boundaries.
The park is named for the fossilized fallen trees which are scattered about and lived in the Late Triassic Epoch, about 225 million years ago. The earliest human inhabitants arrived at least 8,000 years ago. By about 2,000 years ago, they were growing corn in the area. A change in the climate caused the last of the park's pueblos to be abandoned by about 1400 CE More than 600 archeological sites, including petroglyphs, have been discovered in the park.