The state of Arizona is located in the southwestern United States. Arizona has ten National Natural Landmarks that are recognized by the National Natural Landmarks Program. This program was created in 1962 and mandated to ensure the conservation and preservation of sites with outstanding geological and biological features. The program is run by the National Park Service and landmarks are chosen based on their rarity, value to science and education, illustrative character, and condition.
The 10 National Natural Landmarks of Arizona
The federally-owned Barfoot Park in Cochise County has an area of 680 acres and features an extremely high amount of plant diversity. The park also contains some of the highest concentrations of well-developed talus slopes.
Barringer Meteor Crater
Barringer Meteor Crater has an area of 1,432 acres and is one of the largest of its kind in the United States. The impact crater was formed approximately 50,000 years ago from a massive meteor. The site is privately owned.
Canelo Hills Cienega Reserve
The privately-owned Canelo Hills Cienega covers an area of 98 acres and contains some of the most extensive cienega wetland that is undisturbed along the United States–Mexico border. One of the two identified groups of Canelo lady's tresses grows at the site, as well as the rare Gila sucker and Gila chub fish species.
Comb Ridge is owned by the Navajo Nation and covers an area of 11 acres. It is the only known place where tritylodont fossils exist in North America. These fossils resemble those found in South Africa, Eastern China, and Argentina.
Located in Mohave County, the Grapevine Mesa Joshua Trees forest has some of the most impressive Joshua trees in the United States. The federally-owned site has an area of 3,206 acres and contains an impressive diversity of flora.
Kaibab Squirrel Area
The Kaibab Squirrel Area is in Coconino County and has an area of 304,594 acres. Established in 1965, the federally-owned site is illustrative of the habitat for the Kaibab squirrel.
Onyx Cave has an area of 50 acres in Santa Cruz County. Owned by the federal government, the site is situated within Coronado National Forest and has numerous helictites and speleothems.
The privately-owned Patagonia-Sonoita Creek Sanctuary has an area of 314 acres and is among the last of the permanent stream-bottom habitats in the southern part of the state. The site has several Mexican bird species as well as indigenous plant species.
Ramsey Canyon is a gorge with vertical sides cut by a stream. The site is privately owned and has an area of 279 acres, which provides a unique habitat for Mexican plant and animal species that live in the mountains. The area receives the largest number of hummingbirds in the United States.
With an area of 2,369 acres and federally-owned, Willcox Playa is the biggest “dry-lake” in the state. The black mud beneath the surface is rich in fossils from the Pleistocene era. The site is the perfect habitat for a wide variety of tiger beetles and the roosting of thousands of sandhill cranes.
With the exception of Barefoot Park, which was established in 2011, the other national natural landmarks received their designation between 1965 and 1974. The oldest sites are Kaibab Squirrel Area and Ramsey Canyon, which were both established in 1965.