The Grayson County Detention Center in Leitchfield, Ky., pop. 7,000, houses federal prisoners and is expanding.
Though the federal government has only a small role in state prison systems, it is "playing a large and overlooked role in the incarceration of people in jails in rural counties and small cities . . . across the country," Jack Norton and Jacob Kang-Brown report for the Vera Institute of Justice, a nonprofit that promotes incarceration reform.

That's because an increasing number of people detained by the federal government are held in a network of locally run county jails. Federal prosecutors began going after drug offenders more aggressively in the mid-1980s, but federal prisons didn't have the capacity to hold all the new prisoners. So the the U.S. Marshals Service began contracting with county jails, Norton and Kang-Brown report. More recently, Immigration and Customs Enforcement has been sending suspected undocumented immigrants to such jails while awaiting trial for deportation.

"In much of rural America, excess jail capacity is built to be rented to federal agencies and other counties," Norton and Kang-Brown report. "USMS and ICE have played a key role in jail expansion in the United States over the last few decades. The promise of per-diem payments from USMS and ICE has helped local administrators build larger jails and expand their operating budgets. Bigger jails enable counties to incarcerate immigrants and asylum seekers for ICE and pretrial detainees held for USMS, which in turn generates revenue that offsets the cost of detaining and incarcerating local people. County leaders also try to build up local jail capacity in order to avoid paying neighboring counties to hold people for them. The result has been an inter-county carceral arms race in much of the country, producing greater capacity to incarcerate at the local level and bigger and bigger jails."

Though the overall incarcerated population in the U.S. has decreased in the past decade, jail and prison capacity has increased, especially in rural areas that increasingly rely on jails for revenue, according to a recent Vera Institute report. That report also showed that expanding jails as a moneymaker could be a long-term financial risk.