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CNN  — 

Here’s one thing you may not think about when landing at Los Angeles International Airport: Just 11 miles away sits the biggest jail system in America.

With an inmate population the size of a private college and a budget just north of $700 million, the L.A. County Jail is as sprawling and as complex as Los Angeles itself.

The institution – recovering from a massive inmate abuse scandal in 2011 – is one of roughly 2,750 jail jurisdictions across the United States. In midyear 2014, approximately 744,600 people were held in jails nationwide, according to the Department of Justice, most of them facing criminal charges and awaiting their fate in the court system.

The United States is well-known for having the highest prison population rate in the world, and while America’s prisons have come under increased scrutiny with a push for criminal justice reform, there hasn’t been such laser-focus on what’s happening in the country’s jails.

Here’s a look at what you’ll find inside America’s largest lockup in Los Angeles, and what it takes to run such an extensive operation:

17,000-20,000 inmates on average

The average number of inmates in L.A. County on a daily basis fluctuates from year to year. In 2000, the daily average was 19,297 inmates. By 2010, that average dropped to 16,625 before climbing back up, according to Lieutenant Tab Rhodes with the Los Angeles Sheriff’s Department, which operates the jail system.

In 2015, L.A. County housed 17,049 inmates daily on average. To put it another way, 31% more people were in the L.A. County jail than residing on campus at the nearby University of Southern California.

7 facilities across 4,000 square miles

This collection of buildings make up a jail system that’s spread out across a sizable stretch of Southern California, covering a swath of the state that’s nearly twice the size of Delaware.

2,690 inmates over capacity

Nearly all of L.A. County’s facilities were overwhelmed with inmates in 2015. While the Men’s Central Jail was the most populated building in 2015, it was also the only one that didn’t have to deal with overcrowding.

37% of arrests lead to booking

In 2015, there were 304,288 arrests, and 112,538 of those arrestees were booked into the L.A. County jail system, according to the LASD.

Average stay is two months

Overall, the inmate population is primarily made up of nonviolent offenders. According to the LASD, about 37% of inmates have been charged with violent or serious offenses – such as manslaughter, rape, kidnapping, aggravated assault, child molestation, discharge of a firearm and carjacking.

Guards are usually outnumbered by an 8:1 ratio

In order to manage its immense population, L.A. County employs roughly 2,700 sworn officers throughout its system, including 2,259 sheriff’s deputies who guard the inmates and 413 supervisors.

With 10% of its deputies doing administrative work across L.A. County’s facilities, that breaks down to about 7-14 inmates per guard throughout the system.

Half of inmates are pretrial

Remember that jails are different from state and federal prisons in the sense that they hold people after they’re arrested, if they can’t afford to post bail or are considered a flight risk or danger to the public, according to the Vera Institute of Justice.

In L.A. County, more than half of the inmates in the jail system in 2015 had yet to stand trial or be sentenced for a crime. About 38% of inmates had been sentenced to serve time there, while 4% were awaiting transfer to the California Department of Corrections and Rehabilitation. About 5% were being held for parole revocation and other reasons.

85-90% of inmates are affiliated with street gangs

L.A. County guards will tell you that some of their biggest challenges include monitoring a heavily gang-affiliated population in very old buildings.

While there are several hundred street gang affiliations, only two prison gangs are widely represented throughout L.A. County: the Aryan Brotherhood and the Mexican Mafia.

25% are mentally ill

An increasing number of mentally ill inmates find themselves in L.A. County jail because there’s no other place to go within the criminal justice system.

According to the LASD, the overall jail population decreased in 2015, while the mentally ill population was on the rise. Between 2009 and 2016, LASD reports seeing a 60% increase in its mentally ill population.

In essence, L.A. County isn’t just America’s biggest jail. It’s America’s largest in-patient mental health center, too. In early September 2016, a quarter of L.A. County’s inmates received some form of mental health treatment.

This is concerning for mental health advocates and the county for a number of reasons, with one of them being overcrowding. Because many of the mentally ill inmates need to be housed alone, it creates a bed shortage in the general population.

Three hours a week for recreation

This is the amount of time the state of California requires for inmates to have outside of their cells. Many inmates spend an hour or longer in open areas known as day rooms, according to an LASD spokesman.

L.A. County also offers rehabilitation, educational and vocational programs. More than 7,100 inmates participated in the county’s education-based incarceration program during the first quarter of 2016.

$65,000-75,000 for average guard’s salary

For the 2,000-plus guards working in the county jail system, one shift can last twice as long as the standard business day. Guards get $600-800 in overtime pay for a 16-hour shift.

$710 million for the 2014-2015 budget

LASD had a total budget of $3 billion, and spent almost 25% of that on its jail system. That included $562 million for salaries and employee benefits; $142 million for services and supplies; and another $6.5 million allotted for property items such as equipment.