Paquime, or Casas Grandes – a few hours drive from El Paso in Chihuahua, Mexico – is a stunning archeological site, the largest urban center known from the prehistoric North American deserts. Thousands lived here, with multi-story adobe apartments, ball courts and monumental earthen sculptures, a system of reservoirs and canals for drinking water and wastewater. Goods speak of extensive trade connections, and the city exported its own beautiful ceramics. Surrounding peaks are topped with watchtowers and signaling sites, which likely enabled rapid communication across vast desert expanses.
It's so exceptional that archeologists have long looked beyond the region to explain it. Charles Di Peso, who led the first excavations here, believed Toltec colonizers from central Mexico had directed Paquime's construction, as a northern trading center. Some argue it's the work of migrants from Chaco Canyon and the U.S. Four Corners. Yet others propose people from New Mexico's Mimbres Valley – famed for their black-on-white pottery – as its architects and leaders.
But as research on this remarkable site continues, a different picture is coming into focus: the city was built by people with a long history here – Paquime, these findings suggest, was a homegrown Chihuahuan Desert phenomenon.
Dr. Michael Searcy is an archeologists at Brigham Young University.
“Here we are digging,” Searcy said, “and I think we're the only excavation right now in this region of Chihuahua. But every shovel-full of dirt could hold the key to the next piece of the puzzle. The book still hasn't been written on this chapter of the people who lived here. We're writing it right now, I guess you could say. It's awesome – it's so fun.”
Compared to sites in the U.S. Southwest, Casas Grandes has been little studied. But on a hot June day, Searcy is at a dig – leading a team of professionals and grad students from the U.S. and Chihuahua City.
They're probing one of Paquime's great mysteries – how did the city emerge, in apparently planned and coordinated fashion? And what led up to that?
Paquime's urban peak, between 1200 and 1450 CE, is known as the “Medio Period.” But Searcy's team is seeking insight into the 600 years preceding that, which archeologists called the “Viejo Period.”
Chihuahuan Desert grasslands might not seem prime for farming. But perennial rivers flow down from the Sierra Madre here, and desert people were growing corn on the river floodplains, and on hillside terraces, as early 1500 BCE. By the Viejo Period, farming people were living near their fields in pithouse villages.
Few Viejo Period sites have been excavated. Searcy and his colleagues identified this spot – called the San Diego Site – during an extensive walking survey. It's evident what tipped them off. Walking this rise above a floodplain, one sees a stone tool, a mano or metate, a pottery fragment with every step.
“This place is covered in artifacts,” Searcy said, “and that's how we knew it was here, were the artifacts on the surface. Nothing else indicates to us that this is a site other than the artifacts on the surface, which either got kicked up by animals or as soils erode over time, it ended uncovering what's underground.”
Since 2019, they've found Viejo Period homes here. They've a unearthed a rock-lined pit, likely used for roasting agave. And they've found a large communal or ceremonial structure.
And they've used cutting-edge techniques. Scott Ure, also of BYU, surveys these sites with drones. He uses magnetometers to identify buried features. And he'll be leading the use of LiDAR – or 3-D laser scanning – to make digital images, mapping features that could otherwise go undetected.
It benefits the research itself, he said, and the students who are pursuing it.
“It's an expanding an area of interest in archeology,” Ure said, “so that we can be more efficient in data collection, but also find more things without actually putting holes in the ground, which saves time and money. We've been trying to integrate that into our coursework for our students. They're gaining these skills that are at the forefront of archeological research.”
The binational dimension, too, is important.
Nora Rodríguez Zariñán is a professor at the Autonomous University in Chihuahua City. Mexican archeologists have understandably been focused on the monumental cities of the Maya and Aztec – until recently, only a single Mexican archeologist was working in Chihuahua.
Rodríguez Zariñán is determined to change that. She's brought Chihuahua-born grad students to this dig, as part of an effort to raise up a new generation of archeologists here.
“There are not many people speaking about it,” Rodríguez Zariñán said, “so you have a lot of questions that no one can answer. When you come here you notice that there are not answers – we need more research, especially in Northern Mexico.”
The team's goal this summer was to locate additional Viejo Period homes – to gain insight into daily life here 1400 years ago. That hope was thwarted. But they found something just as rich – garbage pits.
“Archeologists love trash,” Searcy said. “It includes a lot of data. Just in one of the trash pits we found evidence of trade, in the shell bead. We found evidence of grinding stone tools, which of course are indicative of agriculture. And then we found corn itself. And loads and loads of ceramics.”
Millions of pieces of shell were found at Paquime – imported from the Pacific Coast, and used in jewelry. But the Viejo Period find shows that these desert people were importing marine shell centuries before the city emerged.
The team is finding other markers of continuity – like shared designs in Viejo and Medio Period pottery. Some of the strongest evidence is from DNA research.
Searcy and colleagues are putting the finishing touches on an extensive analysis of DNA from Viejo and Medio Period burials. But the preliminary results are in. It's clear that the thriving city of Paquime attracted diverse people – including from the Big Bend. But it's also clear, Searcy said, that most Paquimeans had deep local roots, and were descendants of Viejo Period people.
“I think we can more definitively say that the Viejo Period are who became those of the Medio Period and built Paquime,” he said, “which is really cool. And we can see that not only in artifacts, but in DNA as well. Everything seems to be lining up.”
Many mysteries surround Paquime – including the causes of its collapse. But it's increasingly certain that its accomplishments are rooted in the Indigenous people of this desert-mountain region.
