In a two-hour period early on a summer morning, Eldredge says he stopped vehicles containing 120 illegal immigrants, including a U-Haul truck jammed with 29 people. Most are men, though he occasionally comes across families.

Local law enforcement agencies have no authority to arrest people suspected of being in the United States illegally. Police don't call U.S. Immigration and Customs Enforcement unless there are felony charges or a car wreck.

"A lot of the time you look the other way," Eldredge said.

According to a Deseret Morning News/KSL-TV poll, 75 percent of Utahns believe local law enforcement should take an active role in enforcing immigration laws, while 23 percent say it should not.

Furthermore, the poll showed 79 percent say undocumented immigrants, when identified, should be deported. Only 16 percent say they should not.

The migrant traffic in southeastern Utah picks up during harvest season and peak construction times.

Early on Labor Day, trooper Michael Bradford stopped a Ford Explorer with California plates. Eight men were packed into the vehicle, including two in the rear cargo area. The driver, Esteban Cosillos, told Bradford they were headed to Denver to find construction work. He sent them on their way.

Though local police departments see illegal immigration as a serious problem, they don't have the resources to hold migrants for immigration officials.

Up until a year ago, Halliday says, police called the ICE field office in Durango, Colo., when they detained even a few undocumented people. Agents made the 90-mile drive to San Juan County to pick them up for deportation. Sometimes federal investigators stood by during local police DUI roadblocks waiting to apprehend suspected illegal immigrants.

Southeastern Utah, however, is now assigned to the Provo ICE office, some 250 miles away. Halliday says agents told him it isn't worth the drive unless police have 100 individuals in custody.

But with no place to keep that many individuals, authorities in San Juan County let vehicles go.

Migrants typically have little more than the clothes on their backs, which often is layered — four shirts, three pairs of pants, a couple pairs of socks. They sometimes carry a battered suitcase or plastic bag with not much more than a few personal items. But the one thing they do have is cash, especially the coyote, the human smuggler.

Criminal illegal immigrants often prey on the new arrivals.

Last winter in the Mexican Hat area, two robbers dressed as Mexican federales pulled over a vehicle using red and blue lights. They pistol whipped the driver and stole suitcases and cash from the passengers, Eldredge says.