Mississippi Petrified Forest is a petrified forest located near Flora, Mississippi in the United States. It is privately owned and open for public visits. The forest is believed to have been formed 36 million years ago when fir and maple logs washed down an ancient river channel to the current site where they later became petrified. It is one of only two petrified forests in the eastern United States, the other being Gilboa Fossil Forest in New York. It was declared a National Natural Landmark in October 1965.