Saguaro National Park

Saguaro National Park surrounds the city of Tucson, Arizona, in two separate units divided by about 30 miles of urban land. The Tucson Mountain District (West) covers 24,034 acres at the base of the Tucson Mountains and holds the densest saguaro forest in the park. The Rincon Mountain District (East) covers 67,293 acres, rises from desert flats to the 8,666-foot summit of Mica Mountain, and includes a wilderness backcountry with pine and mixed conifer forest above 6,000 feet. The two districts have separate entrance stations; a single $25 vehicle fee covers both for seven days. At roughly 1.2 million visitors per year, the park ranks 28th in annual visitation among the 63 U.S. national parks. Tucson International Airport is only 10 miles from the east district entrance.

The park takes its name and identity from the giant saguaro cactus — the tallest cactus in the United States, reaching 40–60 feet and living 150–200 years. Arms typically begin growing only after 75 years, making a multi-armed saguaro a genuine old-growth plant. The park has no car campgrounds; visitors base themselves in Tucson and drive to one of two scenic loop drives for day use. The west district's Bajada Loop Drive and the east district's Cactus Forest Loop Drive both offer close views of saguaro forests from a car. Saguaro blossoms — the state flower of Arizona — open on May and June nights, and the park draws photographers during blooms and during monsoon lightning storms each summer.

East district (Rincon Mountain): From downtown Tucson, take Broadway Boulevard east to Old Spanish Trail, then south to the Rincon Mountain Visitor Center entrance. The drive is about 17 miles from central Tucson and 10 miles from Tucson International Airport.

West district (Tucson Mountain): From downtown Tucson, take Speedway Boulevard west across Gates Pass Road to Kinney Road, then north to the Red Hills Visitor Center. The drive is about 14 miles. Alternatively, take I-10 west to Avra Valley Road and approach from the north on Sandario Road.

The two districts are not connected by a road through the park. Driving between them requires passing through Tucson, a trip of 30–45 minutes depending on traffic.

By air: Tucson International Airport (TUS) is roughly 10 miles from the east district entrance — the closest airport to any national park in the Southwest. Car rental is available at TUS. Phoenix Sky Harbor (PHX) is about 115 miles north via I-10 and is a common alternative for travelers flying into a major hub.

The two districts of Saguaro National Park sit atop two different geological formations. The Tucson Mountains in the west district are built from volcanic welded tuffs and rhyolite — thick sheets of solidified ash and lava from caldera eruptions roughly 70 million years ago. The hills are geologically young and relatively low, reaching only about 4,700 feet.

The Rincon Mountains in the east district are a metamorphic core complex, one of a chain of unusual geologic features running through the Basin and Range Province of the American Southwest. Deep in the Earth, heat and pressure transformed ancient sedimentary rock into gneiss and schist. As the crust stretched and thinned during the Basin and Range extension starting about 20 million years ago, the denser metamorphic core rose to the surface while surrounding rock pulled away along low-angle faults. The result is a dome of ancient crystalline rock now standing 8,666 feet above sea level at Mica Mountain.

The Tucson Basin between the two mountain ranges was created by the same Basin and Range faulting — a downthrown block between rising ranges that filled with sediment eroded from the mountains above. The deep alluvial soils of the basin support the saguaro's wide, shallow root system, which can absorb water from a large area after monsoon rains.

The saguaro cactus is the foundation of a web of desert species. Gila woodpeckers and gilded flickers excavate nest cavities in living saguaro trunks; when vacated, these "saguaro boots" — hardened chambers lined with dried pulp — become homes for elf owls, small mammals, and other cavity nesters. The elf owl, the world's smallest owl at barely 5 inches tall, is a warm-season resident that nests almost exclusively in abandoned saguaro cavities.

White-winged doves are the primary pollinators of saguaro flowers and one of the most common birds in the park from April through September. Their migration south in October coincides with the drying of the saguaro fruit season. Harris's hawks hunt cooperatively in family groups, a behavior rare among raptors and most reliably observed in the saguaro desert around Tucson.

Javelinas (collared peccaries) travel the desert in groups of 5–15, feeding on prickly pear pads and saguaro fruit. They are active at dawn and dusk and are commonly encountered at both visitor centers. Coyotes, mule deer, Gila monsters, western diamondback rattlesnakes, and roadrunners are present throughout both districts. Black bears and mountain lions inhabit the upper elevations of the Rincon Mountain wilderness above 5,000 feet.

The Hohokam people farmed the Tucson Basin for roughly 2,000 years, engineering canal systems to irrigate crops along the Santa Cruz River. They left petroglyphs throughout the Tucson Mountains, including the concentration now preserved at Signal Hill in the west district. The Hohokam culture underwent major changes around 1400 CE; their descendants include the modern Akimel O'odham (Pima) and Tohono O'odham peoples.

The Tohono O'odham have gathered saguaro fruit in the Sonoran Desert for centuries. The saguaro harvest, which begins when fruit ripens in late June, marks the Tohono O'odham new year and is still practiced as a ceremonial event today. Fermented saguaro wine is used in rain ceremonies to bring the summer monsoon. This relationship between people and cactus is among the oldest continuous cultural traditions associated with any plant in the national park system.

Spanish missionaries established Mission San Xavier del Bac south of Tucson in 1692, and the region became part of Mexico after independence in 1821 and U.S. territory after the Gadsden Purchase in 1853. Ranching and homesteading expanded into the Tucson Basin through the late 1800s.

On March 1, 1933, President Herbert Hoover designated Saguaro a National Monument under the Antiquities Act to protect the cactus forests from collection and encroachment. The monument was expanded in 1961 to include the Tucson Mountain District. On October 14, 1994, Congress passed the Arizona Desert Wilderness Act designating both districts as Saguaro National Park, the 52nd national park at the time.