Casa Grande Ruins National Monument ⓘ

Who were the ancestral Sonoran Desert people? Archeological evidence suggests they may have descended from an earlier hunting and gathering culture that began in this area around 5,500 B.C.E. Over time, as the area grew hotter and drier, wild plants and animals were less abundant. Corn from Mesoamerica was introduced and appears to have influenced a gradual transition from hunting and gathering to a farming existence. Adapting to the arid desert, these early farmers learned to use water from mountain run-offs and rivers to irrigate their fields. By 450 C.E., the people had formed a distinct culture, identified in part by their form of pottery called “red-on-buff.” Archeologists call this specialized culture "Hohokam" but this is not the name of a tribe or a people. O'Odham, Hopi, and Zuni descendents of these ancestral people do not call them Hohokam, and Hohokam is not a word in any of those descendent languages. It is thought that an archeologist misheard the O'Odham word "huhugam" which translates to ancestors (among other meanings). Today we try to use Hohokam only when referring to archeology and its discoveries. We use ancestral Sonoran Desert people when talking about the people who created the pottery, structures, and irrigation systems.

The ancestral Sonoran Desert people discovered that as their villages grew, farm land adjacent to the rivers was becoming scarce. To bring water to land farther away from the rivers, they began to dig canals around 1500 B.C.E., a technique they continued to use for generations. Archeologists have discovered hundreds of miles of prehistoric irrigation canals in the Gila River valley, as well as the Salt River Valley of Phoenix, the Santa Cruz River Valley in Tucson, and on the American Indian reservations of Southern Arizona.

The crops grown by the ancestral Sonoran Desert people eventually grew to include not only corn but several varieties of beans and squash, as well as cotton and tobacco. In addition to their crops, the Hohokam culture continued to make use of the many native plants and animals of the desert. These included cactus fruits, pads and buds, agave hearts (century plant), mesquite beans, and the medicinal creosote bush. The local game included birds, squirrels, rabbits, snakes and lizards, as well as fish and clams from the rivers and canals. Larger game such as mule deer and bighorn sheep could be hunted in the mountains.

Once the idea of irrigation farming took hold, it spread gradually throughout central and southern Arizona. From about 600 to 900 C.E., more villages were established in the Salt and Gila river valleys. Hohokam culture colonists moved up the Verde River valley north of Phoenix, and up the Salt river valley east of Phoenix. They also moved downstream as far west as Gila Bend. Growth of new villages and canal systems also took place along the Santa Cruz river in the Tucson area.

As the ancestral Sonoran Desert people expanded, their contacts with neighboring tribes greatly increased. Trade flourished, bringing material goods and ideas from far and near. They imported turquoise, pottery, pinon nuts, obsidian (volcanic glass) and even sea shells from the Gulf of California and the Pacific Coast. From Mexico came copper bells, iron pyrite mirrors, and parrots. And what did these desert dwellers have to offer in exchange? Their farms produced surplus crops for export. They also traded their finely crafted shell jewelry and pottery. Casa Grande Ruins became a crossroads in the trade system. One major route, reconstructed by archeologists, went from northern Mexico into the Tucson area, and from there into the Gila River Valley.

The idea of a ball game played in an arena or court may have been imported from the Mesoamerican cultures. Archeologists have found over 200 oval-shaped, earthen-sided structures located in large Hohokam villages throughout southern and central Arizona. Some archeologists speculate that a game was played within these courts by two teams and a hard rubber ball. Casa Grande Ruins National Monument preserves an ancestral ball court which can be viewed from a public observation platform.

Desert dwellings changed over time. The earliest types consisted of large oval pits dug several feet into the ground. A brush and pole framework covered the pit, and a layer of mud was applied to the outside. These structures are called “pit houses.” Though pit houses continued to be used, by the 1100's more permanent, above-ground structures began to be built. Using caliche, a natural concrete-like material found under the top soil throughout this region, they built houses with solid walls and flat, caliche-covered roofs.

The 1100’s also marked the beginning of several significant changes. The traditional burial practice of cremation was expanded to include full interment burials. Ball courts were gradually no longer used, and flat-topped, rectangular-shaped earthen structures called platform mounds were built. Villages became more formally organized. Caliche homes were grouped into caliche-walled compounds, and these compounds were arranged around public plazas and public structures. The Great House (Sivan Vah'ki) was built within one of these compounds and today serves as the main visitation area for the public at Casa Grande Ruins National Monument.

The building of the Great House was a major event of the Classic Period (1100 – 1450 C.E.). The best dating methods available indicate that this large, puddled adobe structure was built during the 1300's. The construction appears to have been well planned and organized, requiring tons of material and a huge cooperative effort on the part of many people. Today we can only marvel at the Great House and try to imagine what it was used for. Though many theories have been suggested, we still aren’t sure as to its purpose. All we can assume is that the structure must have been very important to the people who built it.

During the late 1300’s and early 1400’s, the ancestral Sonoran Desert people suffered a period of widespread depopulation and change. Speculations as to the cause have included drought, floods, disease, invasion, earthquakes, internal strife, and salinization of farmland. Today, several indigenous groups have links to the ancestral people. Their cultural traditions, together with on-going archeology and the continued interest of visitors at Casa Grande Ruins, all combine to keep the legacy of the ancestral Sonoran Desert people alive to this day.

Although a great deal of construction has occured at Casa Grande during the 1930s, by 1937 the park still did not have a maintenance and storage facility. For this large building project of the 1930s, Park Superintendent Frank Pinkley obtained the services of the Civilian Conservation Corps (CCC). On November 16, 1937, a carpenter crew of twenty-four men and a foreman arrived at Casa Grande from the Chiricahua National Monument Civilian Conservation Corps Camp CNM-2-A to establish a fifty-man spike camp. Between that date and December 4, they built a barracks, messhall, washroom, storeroom, and a recreational hall in an area just southeast of the current maintenance facilities. The carpenter crew then departed for the main camp and was replaced by another group of CCC men who gave the finishing touches to their camp and then began preparation to construct the maintenance facility in an area south of the residential section.

Not all of the Civilian Conservation Corps enrollees worked in construction. During the time the camp was located at Casa Grande, two to four men were assigned each month to guide visitors through the ruins. Another one to two men were used as mimeograph operators and sometimes as clerk-typists in the Southwestern Monuments headquarters.

Since the architectural style for the new maintenance buildings copied the existing modified Pueblo style, these projects took thousands of adobe bricks. On December 14, 1937, the CCC crew began to prepare an adobe-making area and six days later produced their first adobe. By the end of June 1938 two structures had reached the point that only interior work remained to be done. At that time attention shifted to the erection of an oil house. The CCC concentrated on the oil house so that by November 1938 it was nearly completed. In September a wash rack was built on the south side of the oil house and a gas tank and pump were installed in front.

During May 1939 the CCC men constructed an adobe, modified Pueblo style checking station at the entrance to the monument. Park Superintendent Frank Pinkley had been told to begin to charge a 25 cents admission fee starting May 1939 to each individual entering the monument. As a result, the checking station was erected to provide a building from which monument personnel could collect the charge. This practice had two effects. It angered 38.9 percent of the people who attempted to enter the monument with the result that they refused to pay and left. With CCC help to collect the entrance fee, there was no problem, but, when the CCC left in February 1940, the situation changed. At that time, there was an insufficient number of employees to handle the entrance station and museum, as well as conduct guided tours. As a result, on February 23, 1940, permission was granted to end the entrance fee. Only a 25 cents charge was collected at the museum from those taking a guided tour. Consequently, the checking station was dismantled.

The Casa Grande Civilian Conservation Corps spike camp was abandoned in February 1940 and the men returned to the main Chiricahua camp. On March 8, 1943, a group from the United States Army Corps of Engineers came to the monument and demolished the camp buildings. Salvageable material was hauled away in twenty-five trucks on March 10 and 11, 1943.

This is an artist's depiction of the Casa Grande ("Great House") and its surrounding compound as it may have appeared around 1350 C.E. One of the largest prehistoric structures ever built in North America, its purpose remains a mystery.

Archeologists have discovered evidence that the ancestral Sonoran Desert people who built the Casa Grande also developed wide-scale irrigation farming and extensive trade connections which lasted over a thousand years until about 1450 C.E. Archeologists call a site where there are earthen buildings, red on buff pottery, and extensive canals "Hohokam" but this is not the name of a tribe or a people. Years of misunderstanding have confused the ancestors of the O'Odham, Hopi, and Zuni people with the name Hohokam, which is not a word in any of their languages nor the name of a separate people.

The Casa Grande was no longer used around 1450 C.E. Since the ancestral Sonoran Desert people who built it left no written language behind, written historic accounts of the Casa Grande begin with the journal entries of Padre Eusebio Francisco Kino when he visited the ruins in 1694. In his description of the large ancient structure before him, he wrote the words "casa grande" (or "great house") which are still used today. More became known about the ruins with the later visits of Lt. Col. Juan Bautista de Anza's expedition in 1775 and Brig. Gen. Stephen Watts Kearny's military detachment in 1846. Subsequent articles written about the Casa Grande increased public interest. During the 1860's through the 1880's more people began to visit the ruins with the arrival of a railroad line twenty miles to the west and a connecting stagecoach route that ran right by the Casa Grande. The resulting damage from souvenir hunting, graffiti and outright vandalism raised serious concerns about the preservation of the Casa Grande.

Anthropologist and historian Adolph Bandelier visited the Casa Grande ruins in 1883-1884 and reported on its condition and probable significance. The Hemenway Southwestern Archaeological Expedition of 1887-1888, sponsored by Massachusetts philanthropist Mary Hemenway and led by anthropologist Frank H. Cushing , produced further information on the deterioration of the Casa Grande. As a result, several influential Bostonians urged Massachusetts Senator George F. Hoar to present a petition before the U. S. Senate in 1889 requesting that the government take steps to repair and protect the ruins. Repair work began the following year, and in 1892, President Benjamin Harrison set aside one square mile of Arizona Territory surrounding the Casa Grande Ruins as the first prehistoric and cultural reserve established in the United States.

The General Land Office took over management of the ruins and hired a young man named Frank Pinkley in 1901 to be the first on-site custodian. In 1903 a shelter roof of corrugated iron supported by redwood timbers was built over the Casa Grande, and between 1906 and 1908 major excavations and repairs of the ruins were conducted under the direction of Jesse Fewkes of the Bureau of Ethnology. Most of the lower walls visible today were uncovered at that time. President Woodrow Wilson proclaimed Casa Grande Ruins to be a National Monument on August 3, 1918 and management of the Ruins was transferred to the National Park Service. Frank Pinkley stayed on as custodian and eventually became the superintendent of all southwest monuments. Part of his promotion effort was to produce a wide range of literature about Casa Grande Ruins and to host the annual Arizona Pageant from 1926 to 1930.

Several important construction projects were undertaken during the 1930's. The main part of the visitor center building with adjacent parking lot and entrance road, and a new steel shelter roof over the Casa Grande, were completed in 1932. Between 1937 and 1940, the Civilian Conservation Corps constructed a number of adobe buildings to support park operations. All of these structures remain in use today and are now listed on the National Register of Historic Places. As a result, the general physical appearance of Casa Grande Ruins has changed very little since the 1940's.

Continuing research, ruins repairs, interpretive programs, and visitor center remodeling are all part of the continuing effort to provide the best visitor experience possible, and to fulfill the National Park Service's mission to protect, preserve and make available for present and future generations the many wonders of Casa Grande Ruins National Monument.

Resident Great Horned Owls had triplets in 2012. There has been a nesting pair of Great Horned Owls in the Great House or the Great House's sheltering roof, since May of 2006. Some years are more successful than others as far as fledglings. 2012 marks the ultimate excitement- three young hatched on the walls of the Great House. In 2009 a nesting platform was installed in the roof structure and the young owls relocated. The adults seemed to accept this change and used the nesting platform in 2010 and 2011. The sudden change in nesting area may be due to unknown factors, or some of our longer term volunteers suggest that the original female owl has been replaced (due to her possible death in late 2011) with a new female. No one knows for certain, perhaps you might make several visits and get involved in solving this mystery?

Western burrowing owls ( Athene cunicularia hypugea ) live in open grassland and desert areas in the Western US, Canada, and Mexico. They are unique among birds in that they nest underground in existing ground squirrel, coyote, and badger burrows. Burrowing owls are also commonly associated with humans and will frequently nest in burrows along irrigation ditches, canals, and even in people's yards. Unlike other owls, they are typically visible during daylight hours and are easily spotted as they spend much of their time standing or perching near their nest burrow.

Their breeding season begins mid-March and extends to late August, when some adults and juveniles disperse from their nest burrow. Some owls will stay in the area year round while others migrate further south for the winter. Burrowing owls typically lay a clutch of 7-10 eggs and fledge an average of 3-4 juveniles per nest. Their diet consists of a variety of insects, frogs, lizards, snakes, birds, and small mammals.

Burrowing owls have suffered population declines and range contraction in North America. Burrowing owls are federally endangered in Canada and are listed as a Species of National Conservation Concern in the U.S. Burrowing owls are state endangered in Minnesota and Iowa, and populations have declined in states across the Western U.S.

Sharp eyed visitors and park volunteers spotted Anna's Hummingbirds nesting near the Visitor Center. They are one of the 18 species of hummingbird found in Arizona. It is not unusual to have a hummingbird flit past you if you visit the park doing the blooming season. The birds are very good at finding ANYTHING blooming so lucky park visitors may spot this tiny wonder all spring and summer long. The Southeastern Arizona Bird Observatory has more information on the birds and studies being conducted to learn more.

One of the best things about the Sonoran Desert is its signature plant-- the Saguaro. This cactus is interesting in and of itself, but even more so if you see a saguaro "bird hotel." The Northern Flicker is one resident of the saguaro here in Casa Grande Ruins National Monument. As it pecks its way into the saguaro the cactus works to seal the damage creating what is known as a saguaro boot. There is a saguaro boot on the visitor center's touch table so you can examine one closely if you wish. The flicker, however, is unlikely to permit you to examine it too closely. Please respect its privacy and don't attempt to get too close to its home.

The Sonoran Desert Network has created a Field Guide to the Plants of Casa Grande Ruins National Monument. This webpage will simply bring out some of the highlights of that document.

The word desert often brings to mind the word cactus. Yes, there are some great cacti at Casa Grande Ruins including the signature plant of the Sonoran Desert-- the saguaro. Carnegiea gigantea is an upright cactus with a simple stem with 1 to several lateral branches. It flowers at night, usually in May but sometimes in August if there are plenty of rains. The O'odham peoples have gathered the fruits using traditional long sticks. The fruit has uses that range from mush to wine, jam, syrup, to even using the seeds for oil; the plant's dried 'ribs' can be used for splints, furniture, fences and fodder.

Other common cacti include the barrel, the prickley pear, the "old man" senilis, and various hedgehog cacti. Of these, perhaps most important might be the barrel cactus as it would be the only emergency source of water in the desert. Ferocactus wislizeni , commonly called the barrel cactus, is about as tall as it is wide. Hooked central spines cover the stem and are why its Latin name is Ferocactus or fierce cactus. Called the compass cactus because it tends to lean south toward the sun, these cacti can live up to 100 years. The top of the cactus was lopped off and the interior pulp was crushed as a source of water in extreme circumstances; the seeds were parched, ground, and boiled into a mush; the spines were used as fish hooks by the Pima, and the fruit was made into a candy.

The woody plants in the desert tend to be small and tough. They are expert at conserving, storing, and finding moisture. In the right season, with the right conditions, they can put on quite a show. Here at Casa Grande Ruins woody plants include the mesquite, palo verde, ironwood, and creosote bush. Our Field Guide reminds us that in the Sonoran Desert region trees may not have just a single stem. Trees in this region often have many stems growing from one root, giving them a shrubby appearance. Some trees can, therefore, be thought of as shrubs while some shrubs can be considered trees. Regardless of what you call these larger woody plants, we are glad of their shade and their many uses.

Directly from the Field Guide we learn: "Ferns may not be the first plant that comes to mind when you think of the Sonoran Desert. But there they are, everywhere. In patches of damp shade beneath overhanging rocks, tracing springs out of vertical faces of rock, or covering dry slopes in the oak woodlands. Some even prefer the lack of moisture and the full sun. Desert generally evokes images of endless hot plains and emptiness, not steep slopes of palo verde and brittlebush or the vibrant speckled color of spring in wet years. Wet years and wet places; apparent misnomers in the talk of deserts. But wetness abounds, from minor seeps to creeks to runoff to even the fleeting moisture and shade beneath rocks.In all of these wet places, there are ferns.

Ferns include a remarkable diversity of plants. Across the desert southwest they range from the club-mosses, such as Selaginella, to the diminutive whisk ferns in Psilotum, to the broad range of species in Cheilanthes and the other Pteridophytes, to the related but very different horsetails in Equisetum. This unique group of plants often requires closer attention than it receives, for ferns lack the showy wonder of the flowering plants. But you will nevertheless be amazed, so get yourself a good handlens and look a little closer."

Small and overlooked in the desert are the grasses, sedges, and rushes. Our Field Guide tells us plenty about these plants. "Sedges have edges and rushes are round; grasses are hollow right down near the ground, goes a simple mnemonic taught to botany students.

Grasses are the single most important plant family to human beings. If you had cereal this morning, or enjoyed bread with your sandwich, or really liked that corn tortilla you ate, then you have grasses to thank. In fact, a fairly limited number of grasses account for the majority of our food calories as a human family.

Round tail ground squirrels have developed large colonies in the park. The Nevada Department of Wildlife sums them up by saying "Extreme temperatures with low humidity normally characterize the round-tailed ground squirrel's habitat. The round-tailed ground squirrels prefer flat, sandy areas that are typified by creosote scrub vegetation. The Round-tailed ground squirrel is most active during mornings and evenings, avoiding the most intense heat by retiring to its burrow at midday or seeking shade under a plant. It will climb into bushes not only to obtain leaves, but also to get out of the sun and off the hot sand. This species hibernates from late September or early October to early January, though in some areas it remains active all year."

Often we have bats in our belfry... that is, in our big house. Any bat that you can handle is likely sick, NEVER touch a bat or you may find yourself having to be treated for various diseases including possibly rabies. Bats do a wonderful job of eating insects and pollinating plants (including cacti), we do want them in our ecosystem. We would prefer, however, they pick another roost as they do some damage to the ruins unintentionally. Arizona Game and Fish mentions that "Arizona boasts an amazing diversity of bats: 28 species representing four families. Bats can be found all across our state in every type of Arizona habitat, from deserts to forests." The University of Arizona Cooperative Extension (PDF link) reminds us of some of our more unusual bats: "They feed on pollen and nectar and are critical to the pollination of columnar cacti such as the saguaro, organ pipe, and they also gather nectar from the agaves. Biologists calculate that the pollination of agaves and various cacti would drop approximately 97 percent without our nectivorous bats."

Here a fox found a great hiding place, except that it is in a very public part of the park.