Even as Donald Trump promises a crime crackdown, a deep data dive finds jail populations are soaring fastest in areas that backed him heavily.

A new research has found that incarceration is skyrocketing in rural America, yielding more profits for authorities. Big cities like New York and Los Angeles have been reducing their jail populations, the study discovered; whereas jails in rural counties like Campbell County, Tennessee or Boone County, Arkansas are growing rapidly.

The U.S. has more people in jail than any other country on Earth. According to the country’s Bureau of Justice Statistics, in 2013, there were more than 2.2 million Americans in local jails, state and federal prisons. The researchers claim despite the increase in incarceration rates in rural areas, crime rates have remained largely the same.

Incarceration Trends, a data visualization tool built by the Vera Institute of Justice, aggregated county-level data on the demographics of all of the country’s jails. The researchers then created a centralized, easy-to-sort database that allowed them to spot trends they otherwise would likely have missed.

Rural jail populations have spiked in recent years for a reason. Pre-trial detention rates have tripled nationwide since 1970. Still, as urban pre-trial detention rates have dropped precipitously, they’ve risen the most in the country’s rural counties with fewer than 250,000 residents. Between 1970 and 2013, rural pre-trial detention rates grew some 436 percent.

Jacob Kang-Brown, co-author of the study, says “they’re legally innocent. they’re not yet convicted of a crime, and they’re doing time regardless of that.” The problem, Kang-Brown, adds, often comes down to a lack of resources. Wired reports:

“These rural counties are understaffed, which can lead to long delays in setting court dates. They also sometimes lack the funding that bigger cities use to set up the kind of mental health and drug treatment programs that keep people out of jail.”

However, observers claim many people are going to jail in the rural areas because authorities have turned jailing people into making a money making machine.

About 20 percent of people in jail on any given day are serving time for another jurisdiction. Since 1970, the rate of people from other jurisdictions serving time in rural jails has grown 888 percent. By contrast, that rate has grown only 134 percent in urban areas. This has resulted in some counties building jails much larger than the local community would ever require.

Laurie Garduque, director of justice reform at the MacArthur Foundation, which sponsored the study, blames the media for failing to report a grave issue:

“Not surprisingly given the way the media markets operate, most stories have focused on larger metro populations. This is sort of an example of something hidden in plain sight.”