Incarceration, by the numbers
When I started in the correctional industry, I didn’t know the difference between a prison and a jail. They’re quite different, turns out, in inmate-type, ownership, volume, and character. Here’s a quick overview, for those of you who haven’t been knee-deep in the stuff.

At year-end, 2013, which is the last date for which we have comprehensive numbers from Bureau of Justice Statistics, there were 2.4m people incarcerated in the US. This is about 1 in 100 American adults.
This number, while huge, is just a snapshot, and doesn’t tell the full — and more distressing — story. Nearly 12m people cycle through jails in the US every year. Another 1.56m people are serving longer-term sentences in state or federal prisons, with nearly 45% (688,000) released on parole each year. This means that between 12–13 million people per year are being released back into our communities from prisons and jails; often having been physically, sexually, or psychologically abused; having experienced tremendous anger, depression, and isolation; and coming out with dramatically fewer options for a crime-free, income-earning, taxpaying life than they had prior to their arrest.
Obviously, the US has a problem with incarceration. In order to understand how to think about the problem, you need to understand the different components of our system. Prison Policy Initiative released a brilliant infographic last year that I find extremely helpful.

The source data captured in this chart was found in reports issued between 2010–2013. In brief, of the 2.4m who are locked up:
~721k in local jails
~1.56m in prisons
~71k in juvenile facilities
~34k in immigration detention centers
~23k in military, Indian Country, Territorial Prisons and Civil Commitment facilities
So what’s the difference between a prison and a jail? The terms are confused even within industry, and are frequently mixed up by laypeople and the press. Here’s a primer.
Jails — or detention centers — are operated by municipalities or counties, and designed to hold inmates on a shorter term basis. They are generally located in the communities they serve, and house:
- people who’ve been arrested as they await release, trial or sentencing, or
- people who are serving (typically misdemeanor) sentences of <1 year, although some localities keep people in jail for up to 2 years.
- people who have been sentenced to prison, but are awaiting transfer to that facility, or are in transit between prison facilities.
Jails may be adult or juvenile, and may be run by municipalities, the Indian nation, ICE, the military, or other community organizations for civil commitment.
Jails can be chaotic, as they intake at all hours, ranging from disruptive partiers who need to dry out for a few hours, to mentally ill people having an episode, to those suspected of a violent or other serious crime who are being held pending trial. Approximately 60% are awaiting trial or another court-ordered dispensation — generally these are the ones who are too poor to make bail, or who are waiting for their bail to post, while ~40% are serving short term sentences. They tend to be located in more urban areas, closer to the community.
Prisons — also called penitentiaries or correctional facilities — are secure facilities that are operated by state Departments of Corrections (DOC), the federal government (Federal Bureau of Prisons), or US Territories. They house people who’ve been sentenced to serve prison time, usually > 1 year, but sometimes > 2 years, for felony convictions. They tend to be larger campuses with multiple buildings, and as such (to keep real estate costs low, and to avoid NIMBY fights) are usually found in more remote areas. They’re built for long-term housing, and usually include outdoor, classroom, and programming space.
Confusingly, state, local, and federal criminal justice systems often are structured, funded, and named differently by locality, which makes standardized policymaking, data collection, and performance measurement quite difficult. For instance, in AK, CT, DE, HI, RI, VT, a state-level agency runs both jails and prisons, in some cases even intermingling jail and prison populations within the same facilities. In PA, county jails sometimes are known as county prisons. Most funding for detention and corrections comes from the municipal or state and federal DOCs, but funding for and delivery of some functions within the facilities may come from other agencies; i.e., the Department of Education or the Department of Labor (DOL) may provide in-facility programming.
In short, it’s a complicated mess, with limited data on inputs and outcomes available to start even to puzzle through the problem, much less determine the fixes. It’s an old-fashioned industry that’s been sorely overlooked by innovators and policymakers alike, as those in its grasp are neither wealthy enough to fund change, nor counted via vote. It’s time for the rest of us to stand up, marshal our resources, and fix it.