Colorado's Deadliest Prisons Including The States Most Dangerous Prisoners

10 - Crowley County Correctional Facility

Originally built by Crowley County and opened in 1998, this prison has been operated by the private corrections company CoreCivic since its opening, and the company fully purchased the facility in 2003.

The prison functions as a Level III medium custody facility and has a maximum capacity of approximately 1,894 adult male inmates.

Shortly after the facility opened, a large-scale disturbance occurred in March 1999 involving about 250 prisoners originally transferred from Washington state.

The riot began when an inmate assaulted a food service manager over a dietary dispute, which quickly escalated into prisoners seizing two cell blocks, flooding cells, and throwing rocks in the exercise yard.

The facility is also notable for a significant six-hour riot that occurred on July 20, 2004 while it was housing out-of-state inmates from Washington and Wyoming alongside the Colorado prisoners.

Investigations attributed the unrest to a combination of severe understaffing and friction regarding the treatment of the out-of-state population.

In 2023, the prison was placed into lockdown after an incident occured in several pods which led to a major investigation with one staff member suffering injury's.

Notable inmates at this prison are not currently listed, but the constant attacks on staff make this one of the most dangerous prisons to work in.

9 - Colorado Territorial Correctional Facility

Known as "Old Max," the Colorado Territorial Correctional Facility first opened in 1871, five years before Colorado achieved statehood and is the oldest prison in the state's correctional system.

Originally serving as the primary maximum-security prison and the site of the state's death row, it was heavily renovated and re-designated as a medium-security Level III facility in the 1980s and 1990s.

The prison now houses medium-custody male inmates and features one of the state's two major prison infirmaries but has housed some of the American West's most infamous criminals.

Arguably the prison's most legendary historical inmate, Alferd Packer was known as the "Colorado Cannibal," and was the sole survivor of a prospecting party trapped in the Rocky Mountains during a brutal winter.

He was convicted of manslaughter for killing and eating his five traveling companions and served a portion of his sentence at the territorial prison before being paroled in 1901.

Anton Woode is famous for being the youngest person in Colorado history to be tried as an adult and sent to the prison, sentenced to 25 years for shooting a businessman in the back to steal a gold watch and a shotgun when he was 11-years old.

As the perpetrator of the 2012 Aurora movie theater shooting, which killed 12 people and injured 70 others, James Eagan Holmes was initially sent to the facility's high-security pod after being sentenced to 12 consecutive life sentences without parole.

After Colorado abolished the death penalty in 2020, Nathan Dunlap, who was serving a death sentence at the facility, had his sentence commuted to life without the possibility of parole after a conviction for the 1993 ambush and murder of four employees at an Aurora Chuck E. Cheese restaurant.

Finally, one of the most tragic cases of wrongful execution in U.S. history saw Joe Arridy, a mentally disabled man with an IQ of 46, coerced into confessing to a 1936 murder he did not commit.

Despite immense evidence of his innocence and pleas from the prison's own warden, Arridy was executed in the prison's gas chamber in 1939, later granted an official pardon by the Governor of Colorado in 2011.

There have been a number of major riots at the facility over the years including one in 1929 that became known as the "Canon City Mutiny," and saw several staff taken hostage and multiple escape attempts.

On December 30th, 1947, 12 inmates executed a highly coordinated escape from the facility that became the subject of a famous 1948 semi-documentary movie with all inmates later re-captured or killed.

8 - FCI Englewood

Located in the Denver suburb of Littleton, Colorado, FCI Englewood opened in 1938 and primarily operates as a low-security federal correctional institution for men.

The prison is frequently used by the Federal Bureau of Prisons to house high-profile white-collar criminals, disgraced politicians, and inmates whose notoriety makes them targets in maximum-security environments.

One notable inmate to serve time here is Thomas Lane, one of the former Minneapolis police officers convicted in connection with the 2020 killing of George Floyd.

Another is the former television spokesperson for the Subway sandwich chain, Jared Fogle who is serving a 15-year sentence for traveling to engage in illicit sexual conduct with minors.

South Carolina police officer, Michael Slager, who was caught on bystander video shooting and killing Walter Scott, an unarmed Black man fleeing a traffic stop in 2015, is currently serving a 20-year sentence at Englewood.

Both Timothy McVeigh & Terry Nichols were held in pre-trial detention at Englewood under intense security before their eventual convictions and transfers to higher-security locations.

Several notable incidents to include at this facility, with inmate Alan Todd May managing a remarkably low-tech escape that involved him simply checking out a prison vehicle for an alleged job and driving entirely off the property.

Due to the chaos of the impending Government shutdown, authorities didn't realize he was missing for five days and he was on the run for almost 5-years until U.S. Marshals tracked him down and arrested him.

In April 2012, the entire facility went into an emergency lockdown after mailroom staff flagged an envelope addressed to an inmate containing an unidentified white powdery substance thought to be Anthrax but later deemed non-toxic.

7 - Fremont Correctional Facility

Located in Fremont County just outside Cañon City, Fremont Correctional Facility is part of the massive East Canon Complex.

Opened in 1962, it is a Level III medium security facility and is spread across 51 acres, making it the second-largest state facility in Colorado, capable of housing over 1,600 male inmates.

Fremont is structured heavily around rehabilitation, containing large-scale industrial labor programs and specialized, mandatory rehabilitation tracks.

One of the most notorious serial predators in recent Colorado history, Travis Forbes, is currently serving life in prison without the possibility of parol after a brutal murder and another attack on Lydia Tillman, in Fort Collins.

Lester Ralph Jones, sentenced to life imprisonment without parole for the 2007 kidnapping and murder of Paige Birgfeld is also serving time at Fremont.

Finally, a central figure in a notorious 1990s gang-related crime spree in Denver, Robert "Freddy" Trujillo was convicted of first-degree murder and conspiracy, but later became highly involved in the prison’s internal religious and peer-led counseling programs.

On December 4th, 2019, a commercial boiler located at the facility suffered a sudden "catastrophic failure" and exploded, instantly killing a Colorado Department of Corrections staff member who was working on duty nearby.

6 - Limon Correctional Facility

About 80 miles east of Denver in Lincoln County and situated on the States Eastern plains, sits Limon Correctional Facility, a level IV, close security state prison that operates just one step below maximum security.

The site encompasses 13 buildings on a 320-acre site, wrapped in a heavy double-perimeter fence that keeps some f the state's most volatile and violent offenders inside.

Limon has a history marked by severe inmate-on-staff violence, targeted stabbings, and modern contraband struggles.

Correctional officer Eric Autobee was brutally beaten to death in the facility's kitchen by inmate Edward Montour Jr on October 18th, 2002, with Montour already serving a life sentence for the murder of his infant daughter.

In September 2007, the facility faced another shocking staff assault when an inmate snuck up on corrections officer Pam Kahanic and slashed her throat with a smuggled box-cutter knife, but she survived and returned to work just 6-weeks later.

Inmate-on-inmate violence has also occasionally turned lethal with inmates Jeffrey Heird and Joshua Edwards both attacked and killed in the facility, and a recent murder, Paul Hack died in 2023 as the result of an attack.

Notable inmates to serve time here include one of the most prolific, though lesser-known, serial killers in American history, Robert Charles Browne who claims to have killed over 48 people across multiple states between 1970 and 1995.

Freddie Glenn, a central figure in a horrific 1975 crime spree in Colorado Springs, was convicted of multiple murders and most notably the kidnapping and killing of 18-year-old Karen Grammer spent a large portion of his sentence here.

Murderer Michael David Whyte, who was convicted of killing Darlene Krashoc, a fellow soldier, was transferred to Limon to serve out his life term at the facility.

5 - Centennial Correctional Facility

Opened in 1980, Centennial Correctional Facility has a unique architectural and administrative history with it originally serving as the state's main Level V maximum-security prison until the neighboring Colorado State Penitentiary was built in 1993.

Today, the prison is split into two distinct north and south segments and is heavily utilized for the Department of Corrections' Residential Treatment Program that manages offenders with severe mental illness.

All offenders in the South building are in Administrative Segregation which is also known as solitary confinement.

One of the prisons most notable inmates, Christopher Scarver is currently serving three consecutive life sentences without parole for the murders of Jesse Anderson and serial killer Jeffrey Dahmer.

Another notorious inmate, Devon Michael Erickson is serving two life sentences without parole for his part in the 2019 STEM School Highlands Ranch shooting.

4 - Sterling Correctional Facility

Currently the largest prison in the Colorado Department of Corrections system, Sterling Correctional Facility opened in 1999 and functions as a mixed-custody facility, housing approximately 2,500 inmates.

Due to its size and the high-security nature of its population, Sterling has faced significant scrutiny over the years regarding inmate safety, gang activity, and operational challenges.

Sterling experienced an alarming spike in violence between 2010 and 2013, resulting in the homicides of several prisoners that were the result of classification errors and the prison’s failure to adequately protect vulnerable populations.

The facility was placed on a strict lockdown after multiple inmates launched a coordinated assault on correctional officers in the prison dining hall that left four guards hospitalized with severe injuries.

Many notable and dangerous inmates have served time here including prolific serial killer and former FBI informant Scott Lee Kimball, who was linked to the murders of four people and attempted a sophisticated escape plot at the prison.

Troy Graves, known as the "Fort Collins Serial Rapist," terrorized both Colorado and Philadelphia, committing a string of sexual assaults and the murder of a university student before his capture in 2002.

Another highly dangerous inmate, Marc Patrick O'Leary was a serial rapist whose highly calculated crimes across Colorado were the subject of intense investigative work that inspired the book and television series "Unbelievable."

3 - Colorado State Penitentiary

Often confused with the federal Supermax, ADX Florence, this state-run facility is operated by the Colorado Department of Corrections and was first established in the 19th century.

The prison is designed to house the state's most volatile, violent, or escape-prone offenders, largely utilizing long-term solitary confinement conditions and has been the backdrop for some of the bloodiest events in Colorado's correctional history.

One of the deadliest prison riots in U.S. history took place at this prison on October 3rd, 1929, when inmates staged an uprising, taking several guards hostage and setting fire to prison buildings.

By the time law enforcement and the National Guard regained control, 13 people, including five inmates and eight correctional officers, had been killed.

The penitentiary has held a grim roster of Colorado's most infamous state criminals over the past century, including Jack Gilbert Graham, the man responsible for bombing of United Airlines Flight 629 that killed everyone onboard.

James Eagan Holmes, serving a sentence of over over 3 millennia for his attack on the Aurora movie theatre was held here for a time before being moved to USP Allenwood in Pennsylvania.

Sir Mario Owens is another prisoner who was sentenced to death for the murder of witnesses of a previous murder for which he was convicted, but is now serving life without parole.

2. USP Florence - High

While this prison shares the same complex as the famous ADX Florence, it is a separate facility that is designed to house inmates who require tight control due to histories of violence, escape attempts, or gang affiliation but not ADMAX segregation.

Florence High has a reputation as one of the more volatile high-security pens in the federal system with racial tensions, gang wars, and internal scandals often making headlines.

On April 20th, 2008, a massive 30-minute riot erupted in the recreation yard involving roughly 200 prisoners who threw rocks and home-made shanks before officers opened fire, killing two armed inmates.

Between 1995 and 1997, a rogue group of federal correctional officers who called themselves "The Cowboys" routinely abused inmates and were accused of beating and choking handcuffed prisoners.

The only step down from the most secure conditions, this prison is a who's who of convicted terrorists, organized crime figures and murderers.

Ahmed Ressam, an Algerian national, was convicted in 2001 of terrorism conspiracy for planning to bomb Los Angeles International Airport on December 31, 1999.

Perry Roark is another former prisoner considered to be the most dangerous and is one of the founders of the Dead Man Incorporated prison gang, currently serving time for racketeering conspiracy, murder and trafficking.

Green River Killer, Gary Ridgway who is serving 49 consecutive life sentences plus 480 years, spent a portion of his sentence at this facility before his transfer to Washington State Penitentiary in 2015.

1 - ADX Florence Supermax

Officially known as the United States Penitentiary Administrative Maximum Facility, it is currently the only federal supermax prison in the United States and has been dubbed the "Alcatraz of the Rockies."

Opened in 1995 as a direct answer to the security and structural failures at other prisons, the whole prison operates under a system of near-total social and sensory isolation.

Inmates spend 22 to 23 hours a day inside a 7-by-12-foot concrete room with the desk, stool, and bed frame made entirely of poured, molded concrete.

A single 4-inch-wide vertical slit serves as the window, however, inmates cannot see the sky, nearby highways, or even each other due to the facility being partially underground.

The prison as a whole contains a multitude of motion detectors, cameras, and 1,400 remote-controlled steel doors with the perimeter featuring pressure pads and 12-foot razor wire fences.

For an hour or two a day, pending strict good behavior, inmates are handcuffed and escorted to a small, fenced-in outdoor cage or an empty concrete pit for recreation and exercise.

Interactions with guards are minimal, and physical contact with other human beings is virtually non-existent, with phone privileges and non-contact family visits, severely restricted.

The prison houses a dark directory of domestic terrorists, foreign operatives, cartel leaders, and double agents, with everyone on site at risk of escape or attack.

The notorious former leader of the Mexican Sinaloa Cartel, Joaquín “El Chapo” Guzmán was placed here after several escape attempts at other prisons where he was held.

British-born Al-Qaeda operative Richard Reid, known as the "Shoe Bomber," is currently serving three life terms plus 110 years after his failed 2001 transatlantic flight bombing attempt.

Larry Hoover, the co-founder of Chicago's powerful Gangster Disciples street gang was transferred here to halt his ability to run the gang from behind bars and is currently serving 6-life terms.

In 2005, Aryan Brotherhood members Silvester Rivera and Richard Santiago managed to fatally beat fellow inmate Manuel Torrez during a rare joint recreation period and it is currently the only homicide recorded inside.

Joseph Romano was considered to be so dangerous after plotting to murder the judge and federal prosecutor who helped sentence him to 15 years in prison, he was moved here after plotting kill another undercover officer who had taken part in the investigation.

The facility is the final stop for those who are simply too dangerous to be housed in any other prison and most who come into its walls are never leaving unless transferred out to other prisons for good behaviour.

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