National public discourse has turned to the problem of mass incarceration in recent years, and certain places tend to capture most of the headlines, bubbling up to the forefront: overcrowded state prison systems, private facilities run by profit-seeking corporations, and mega-jails such as Rikers Island. These places help illustrate what’s wrong with our nation’s system of mass incarceration, which locks up 2.2 million people. But some troubling parts of our incarceration problem remain largely invisible—like the 300-bed jail in Grant County, Kentucky.

Small counties have fueled the country’s jail growth in the past few decades, and are continuing to expand even as the use of incarceration in bigger cities begins to slow down. This phenomenon—brought to light through Vera’s Incarceration Trends data tool and explored in a new report on rural jail growth by Vera and the MacArthur Foundation’s Safety and Justice Challenge—is widespread. It’s also insidious: there are more than 2,600 small-county jails; when a single jail expands from, say, 100 beds to 200, it may not seem significant, but the numbers add up quickly when multiplied over thousands of counties. This should be cause for concern. 

Jail expansion in rural counties is oftentimes not a slow, inevitable trend, but a result of a new facility opening. In Terrebonne Parish, Louisiana, for example, a jail facility built in 1993 was intended to alleviate overcrowding. The new facility increased the jail capacity from 150 beds to up to 650—far more than the parish needed at the time. But soon enough, by 2008, the jail was full—and as the data show, the pretrial jail population (those legally presumed innocent while they await the resolution of their case) spiked and exceeded the statewide average. Earlier this year, the parish opened a women’s facility to make more room in the main jail.

Like most of the country, the increased use of jail in Terrebonne Parish doesn’t track with increased crime, which peaked in the 1990s. And growing the jail is not likely to have helped drop crime rates either, as research has concluded that our country’s increased use of incarceration had only a limited effect on crime declines.

In Grant County, Kentucky, it’s also pretty easy to guess what year the jail was expanded when you look at the chart below that shows the county’s jail population trend. Officials in Grant County intentionally increased the jail’s capacity beyond what was needed—from 28 beds to 300—in order to house people sent from overcrowded state prisons. This kind of exchange is a common practice, especially in small, rural jails where sheriffs receive per-diem payments for every person they hold on behalf of state prisons or the federal immigration enforcement agency, for example.

This may seem like a decision that only has the upside of revenue and jobs for the county. But political winds change, and when state or federal agencies decide to stop sending people to the county, as is happening right now in Grant County, the taxpayers in these counties are left with millions of dollars in construction debt for a jail facility that is far larger than necessary. And even more troubling, as availability of jail space in Grant County grew, so did the use of pretrial detention in the county. There are more than four times as many people held pretrial on an average day than before the jail expanded. Prior to building out the jail, the pretrial incarceration rate in Grant County was 23 percent below the state average; by 2011, it was 78 percent above the state average. Research has shown that even a few days in jail can result in job loss and an increased risk of future criminal justice system contact, meaning that more Grant County residents than ever are now at risk of starting cycles of incarceration that have devastating consequences for families and the entire community. 

Both of these examples demonstrate an important consequence of building a new, bigger jail: it sets in motion a trajectory of filling jail beds that is difficult to stop—and that sweeps more and more people into a cycle of incarceration, which can be difficult to escape. 

Private prisons—which hold fewer than 9 percent of state and federal prisoners—are economically incentivized to fill their jail beds, a fact that has understandably fueled public outrage, investigative journalism, and even airtime in last year’s presidential debates. But jails confront similar financial incentives when they are reimbursed for people they hold for other agencies, especially when they are under-resourced. And when the state and feds send fewer people, local taxpayers are on the hook for the budget shortfall, while the availability of more jail beds invites the specter of unnecessary pretrial detention. 

For a long time, small counties have expanded their jails without knowing the history of their trends and how they compare to other counties. Now, the Incarceration Trends data tool (recently updated with pretrial population data) shows jail growth trends—like the ones shown here from Grant County and Terrobonne Parish—for every U.S. county. Every community, especially those facing jail overcrowding and the prospect of jail construction, can use it to look at their own growth trends and ultimately, start pulling the levers of their justice system in a way that works to keep people out of jail who don’t need to be there. 

The construction of local jails is a big investment, often making up a significant share of local budgets and, especially in rural communities, setting up a source of employment that’s not easily replaced. Underlying these fiscal realities are the human costs of people’s unnecessary involvement in the criminal justice system, including lost jobs and family separation. The costs and consequences of constructing a new jail should be measured carefully, because as many counties have seen: if you build it, they will come.