Apprehensions along the Arizona-Mexico border have fallen, but in the Sonoran Desert, the migrant death toll remains disproportionally high.
In July 2026, recorded migrant deaths peaked at 19, the highest death toll for July in two years, according to the Pima County Office of the Medical Examiner and Humane Borders. So far this year, there have been 89 migrants’ bodies recovered compared to 102 in total for 2025. Remains recovered in a single calendar year may not coincide with the actual year of death, as most remains are found after several months to a year of the individual’s death.
In contrast, attempted migrant crossings, or what the Border Patrol calls “encounters” in Arizona’s Tucson and Yuma border sectors dropped by roughly 61% from fiscal year 2025 to fiscal 2026, according to U.S. Customs and Border Protection data. From fiscal 2024 to fiscal 2025, migrant crossings dropped by 88%.
The U.S. Customs and Border Protection data and data from Humane Borders, a Tucson humanitarian organization, do not cover identical time periods nor exact geographical areas. However, the decline in migrant deaths has not kept pace with the decline in migrant encounters, suggesting that even as fewer people attempt to cross the border, those who do may continue to face significant risks in the Sonoran Desert.
Aid workers who have spent years in the field providing water stations in the desert agree, “The amount of people crossing has significantly decreased,” said Joel Smith, operations manager for Humane Borders. “No matter what the politicians in Washington say, it’s much quieter now than it was during the George W. Bush years.”
The Harder Path
Working with the Pima County Office of the Medical Examiner, Humane Borders tracks deceased migrant data in an interactive map, which shows the location where human remains have been found.
“What I like to point out to people when you’re looking at that map,” said Miranda Haley, a representative of the nonprofit group that maintains water tanks in remote areas of the southern Arizona desert. “I want you to see what’s not on the map.”
Study it closely, she said, and a pattern emerges: The recorded deaths are clustered along roads. It doesn’t necessarily show where people are dying, but where the bodies have been reached.
“The desert is vast. It is very good at cleaning itself, and there are large areas that are mostly inaccessible except on foot,” she said. “So what’s not on there are thousands and thousands of deaths that we do not have recorded because we simply have not found the remains.”
As border enforcement tightened around ports in 2025, crossings did not stop, they moved. Border activists say migrants attempting to cross the border illegally were forced to find harsher routes.
“In 2006, it was easy. They just walked through the Altar Valley,” Smith said. “Now you rarely see anybody walking through the Altar Valley because the Border Patrol has flooded the Altar Valley.” The area is a long north-south valley, roughly northeast from Sasabe on the border to west of the Tucson Mountains.
Now, Smith said, migrants are crossing through mountains where there’s less surveillance.
“They’re in the Baboquivaris, which is much more inaccessible, more steep, much more challenging,” he said, adding that border patrol agents don’t favor that terrain either. “Once they get off the roads, they have to go by foot, and it’s some tough terrain.”
Mónica Ruiz House, the media outreach and digital organizing coordinator for No More Deaths, another Tucson humanitarian group, pointed to research from the University of Texas at El Paso and the University of Arizona’s Binational Border Institute describing the same dynamic.
“The more surveillance, the more border tech, the more border militarization you have, the deadlier it becomes,” Ruiz House said, “because it becomes much harder to cross in easy crossing routes, because those become surveilled.” In the West Desert area, which includes the Sonoran and Mojave Deserts, they said, reaching a highway can mean walking 60 miles in 115-degree heat.
Both the Border Patrol and humanitarian groups agree that migrants are being pushed to dangerous terrains. The only difference in opinion is who is at fault.
Humane Borders blames greater border surveillance as the main reason for migrant deaths in Arizona’s borderlands, while U.S. Customs and Border Protection blame smuggling organizations, among other factors.
Many migrants who attempt to cross the border illegally are working with smuggling organizations who may push them to take the rougher terrains to cross, according to the U.S. Customs and Border Protection.
“Smuggling organizations are adaptive and routinely put profit above human life,” a Border Patrol spokesperson said in an email. “They may exploit remote and dangerous terrain, provide illegal aliens with misleading information and abandon individuals during dangerous crossings.”
The spokesperson said the Border Patrol has agents trained as emergency medical technicians as well as Search, Trauma and Rescue teams, who can respond in remote and austere environments, including the Sonoran Desert.
The Unknown Numbers
The Pima County Office of the Medical Examiner reports that of the 4,517 migrant remains found in the Arizona borderlands since 1981, 1,639 are unidentified. The Border Patrol, Humane Borders and No More Deaths agree that the numbers are only a fraction of the number of migrants who die crossing the border.
“We talk to statisticians across the country regularly. We get mixed reports, but what I hear pretty consistently is that our death numbers seem to reflect probably about half to maybe a third of what is actually out there,” Haley said. “I’ve heard numbers as high as 10 times what is reported.”
When asked if that matches what Humane Borders volunteers see in the desert, Smith says it goes even further. Smith says that scavengers like coyotes and vultures scatter remains quickly. On a search, “if you’re lucky, you find a bone,” he said.
“I would say we don’t even find one in ten,” he said. “And that’s going to scare and anger people.”
A smaller gap to estimate, Smith says, is about procedure. Smith said Border Patrol counts only the remains its own agents find.
“If a sheriff’s deputy finds remains, it doesn’t get counted. If you or I find remains, it doesn’t get counted,” he said, “even though the medical examiner has the remains on a table at the morgue.”
Customs and Border Patrol didn’t respond to whether its published death totals leave out the remains recovered by non-agents. However, a 2024 report by the U.S. Government Accountability Office explained that Border Patrol officials said their policies could exclude some migrant deaths when agents are not directly involved with locating or identifying the remains.
According to the 2025 Pima County Medical Examiner Annual Report, the office documented 106 migrant remains recovered during the fiscal year 2025. The Border Patrol Tucson sector reported 70 migrant deaths for the same period.
The Pima County Office of the Medical Examiner reported 36 more cases than Border Patrol. However, the two agencies use different reporting methods and geographic boundaries. Still, the difference raises questions about the accuracy of the recorded migrant deaths along the Arizona-Mexico border, and whether federal statistics are capturing the full extent of migrant fatalities.
Where the Water Can’t Reach
Humane Borders tries to help migrants travel through the desert by setting up water stations with poles and flags and one or more 55-gallon blue industrial strength plastic barrels, which are refilled as necessary. But sometimes the barrels are vandalized. Smith listed what it costs to repair a station: A new barrel costs around $100 and the poles and flags are about $50. The locks that keep the water barrel from being opened and contaminated run roughly $85 and the stands cost less than $5.
Damage to the barrels can run from opened spigots to barrels that have been stabbed, shot or attacked with power tools and accelerants. Smith said the vandalism rises in the winter. Haley said that “vigilantes and alt-right provocateurs are very fair weather;” they don’t like coming out in the extreme heat and during monsoon season. To her, it’s easier working during the extreme heat and storms because in those conditions, the vandals stay home.
When setting up the water stations, money and vandalism aren’t the only concerns. Another major limitation is the roads. “With our current methodology, we are very road dependent,” Smith said.
Near Tucson there’s a road every six miles or so, “but if you go out west, you can go over 20 miles and not see a road,” he said. Water can be placed only as far as a truck can drive plus the length of the water hose.
Much of Cabeza Prieta National Wildlife Refuge and Organ Pipe Cactus National Monument on the Mexico-Arizona border are federally designated wilderness areas, which means new roads cannot be built. That also means water can’t be placed in some areas where people are known to die while crossing the border.
Earlier this month, additional roadblocks were placed by two federal agencies in humanitarian group efforts to offer water to border crossers. On Oct. 1, 2026, Humane Borders announced that federal agencies had declined to renew their permits for 12 water stations across southern Arizona. The National Park Service denied permission for water stations at Organ Pipe Cactus National Monument, and U.S. Fish and Wildlife Service denied permits affecting Cabeza Prieta National Wildlife Refuge.
Raquel Montez, superintendent for Organ Pipe Cactus National Monument, sent a letter to Humane Borders rejecting their permit renewals, according to an article published by the Tucson Sentinel. The letter expressed concern that placing the water stations in remote federal lands facilitates unauthorized border crossings through harsh desert environments.
“While we understand the stated intent is to assist migrants and provide lifesaving water, their presence on park service lands inadvertently encourages migrants to travel deeper into dangerous terrain under a false sense of security,” Montez wrote.
Haley has a standard reply to those who oppose placing water barrels in the desert, because it encourages migrants to cross. Nobody, she says, leaves their family and their home to hike a dangerous desert for her “warm, slightly chlorinated tasting water.”
Haley said they put out water stations where the data shows there are deaths. “Those red dots on that map, they show up long before the blue water barrels do,” she said. “It’s already happening. The very least we can do is put out water.”
Weather Patterns and Night Crossings
While extreme heat remains the biggest cause of migrant fatalities, Arizona’s monsoon season is also a concern. Floods can wash out migrant remains, Haley said, “pick up and disperse them or just obliterate them.”
Haley said her group’s water runs to refill barrels often get cancelled when storms are coming, because volunteers stranded in a flooded canyon only adds to the problem. Smith has returned to stations and found debris piled against the stand and at least one flood carried a barrel away entirely.
Enforcement adds to the danger for migrants during night crossings. When groups of migrants run into agents, Haley said, they “tend to scatter and panic.” And in steep canyon country, the desert devours light at night, she said. Falls and flash-flood drownings have been the cause of several recorded migrant deaths.
Still, recovery figures can’t prove seasonal death patterns, and Ruiz House was careful in considering the correlation.
“One thing that’s really important to emphasize is that the actual date of recovery is not the date of death,” Ruiz House said. “So it’s really difficult to say if monsoons were a direct cause of that, and to establish that causal relationship.”
Someone’s remains recovered in July may have died weeks, months or even a year earlier. From 2020 to 2023, 27% of migrant remains recovered in Pima County had an estimated postmortem interval of more than six to eight months, according to data from the Pima County Office of the Medical Examiner.
Prevention through Deterrence
Haley said she expected disagreement over how to fix migration to follow party lines, but the responses were surprising.
“When you are talking to conservative people on the border, Republican ranchers who are staunchly Republican, they will say the same thing to you that I would say, which is that we need a better immigration policy that allows people to come and work here (in the U.S.), maybe only for a little while, and then go home and then come back. But it shouldn’t be prevented through deterrence,” she said.
Haley said that when looking at the location of migrant deaths, one statistic stands out. A sudden jump in deaths followed enforcement operations of the 1990s, she said.
“Operation Gatekeeper, Operation Hold the Line, they were all born out of the policy of prevention to deterrence,” she said. “We have over 20 years of evidence showing that prevention through deterrence does not work at keeping people out. What it does is drastically increase the number of deaths in the desert.”
Operation Gatekeeper was a U.S. border enforcement initiative under President Bill Clinton and Attorney General Janet Reno with a goal to stop unauthorized border crossings along the 66-mile San Diego sector of the border. Operation Hold the Line was a 1993 Border Patrol enforcement initiative in El Paso to block unauthorized border crossings through physical lines of agents and vehicles.
“The map that you’re looking at, all of those red dots, all of those deaths are engineered by policy,” Haley said. “They are not inevitable. It is an engineered death.”
The Border Patrol had no further comment on questions about prevention through deterrence or the research linking it to deaths in the desert. Their statement did acknowledge “the extreme dangers posed by the Sonoran Desert, including heat exposure, dehydration, difficult terrain, and the exploitation of vulnerable people by transnational criminal organizations.”
Haley often reminds people that illegal entry is by law a misdemeanor, “it does not come with a death sentence, and it certainly doesn’t come with a death sentence before it’s been tried in court. But the prevention through deterrence policy has turned the desert into a weapon, and it is skipping the court system.”
She said that what migrants tell aid workers remains strikingly consistent. She said it’s the same sentence in different languages, dialects and accents: “I would not be here if I had any other option. But I would rather die in this desert trying than watch my family starve in front of me.”
Haley said she does not believe her work is drawing migrants to cross illegally since they have been crossing long before water stations were placed in the desert.
“There is not a more painful or lonely way to die than the way that you die in the desert,” she said.