Special Report

The Biggest Prisons in California

Public Domain / Wikimedia Commons

California has the country’s second-largest prison population after Texas, but the Golden State has greatly reduced the number of inmates in its state prison system after years of sentencing reforms. The coronavirus pandemic also led to a spike in the release of thousands of nonviolent offenders who had 60 days or less to serve in an effort to maximize space.

Today, about 95,000 people are serving time in California’s state-run correctional facilities, down from a peak of 165,000 in 2006, a population so large that federal courts mandated the state find a way to ease prison overcrowding. In 2015, California voters had their say, passing Proposition 47, a ballot measure to further reduce overcrowding by lowering penalties for nonviolent crimes like shoplifting, larceny of low-value items, and possession of small amounts of illegal drugs.

But recent data shows that most of California’s state-run adult correctional facilities still house more inmates than the facilities were designed to hold. Prison overcrowding typically requires measures like converting double-occupancy cells into triples and filling common areas like gymnasiums with bunk beds. Prison overcrowding increases the chance of violence encounters between inmates, reduces sanitary conditions, and adds more security challenges for prison staff. (Also see, California is the state with the most people on death row.)

To identify the biggest prisons in California and how crowded they are, 24/7 Wall St. reviewed inmate counts in 32 of the state’s adult correctional institutions. Data is as of March 1, 2023, as reported by the California Department of Corrections and Rehabilitation Division of Correctional Policy Research and Internal Oversight Office of Research. Inmate counts include all boarders confined in state-run prisons. All data came from the California Department of Corrections and Rehabilitation.

Out of the 32 state correctional facilities with data, only eight hold fewer inmates than the facility was designed to hold. These include the California Institution for Women in the city of Chino, east of Los Angeles, and the California State Prison in Sacramento.  

At the other end of the spectrum, the state’s largest prisons by inmate populations are also among the most overcrowded. These include Avenal State Prison in the central San Joaquin Valley and the California Rehabilitation Center in Riverside County, which are run at 159% and 166% overcapacity, respectively. (This is what prisoners are paid for forced labor in every state.)

Five California state prisons, including Avenal and CRC have occupancy rates of more than 150%, meaning that the facility is holding about one extra inmate for every two it was intended to hold. The average occupancy rate for all 32 correctional facilities is 118%.

Here are California’s biggest prisons.

Click here to see our detailed methodology.

Public Domain / Wikimedia Commons

32. California Institution for Women (CIW)
> Inmates: 983
> Capacity: 1,281 – #32 most on list
> Percent occupied: 77% – #31 highest on list
> County: San Bernardino County

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31. California State Prison, Sacramento (SAC)
> Inmates: 1,513
> Capacity: 1,828 – #28 most on list
> Percent occupied: 83% – #28 highest on list
> County: Sacramento County

30. Pelican Bay State Prison (PBSP)
> Inmates: 1,602
> Capacity: 2,380 – #16 most on list
> Percent occupied: 67% – #32 highest on list
> County: Del Norte

Public Domain / Wikimedia Commons

29. California Correctional Institution (CCI)
> Inmates: 1,900
> Capacity: 2,172 – #24 most on list
> Percent occupied: 88% – #26 highest on list
> County: Kern

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28. California Medical Facility (CMF)
> Inmates: 1,975
> Capacity: 2,318 – #18 most on list
> Percent occupied: 85% – #27 highest on list
> County: Solano

Courtesy of Chuckawalla Inmante Family Council via Facebook

27. Chuckawalla Valley State Prison (CVSP)
> Inmates: 2,094
> Capacity: 1,738 – #30 most on list
> Percent occupied: 121% – #14 highest on list
> County: Riverside

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Courtesy of Roy L. via Yelp

26. California Institution for Men (CIM)
> Inmates: 2,196
> Capacity: 1,604 – #31 most on list
> Percent occupied: 137% – #8 highest on list
> County: San Bernardino

Public Domain / Wikimedia Commons

25. Central California Women’s Facility (CCWF)
> Inmates: 2,355
> Capacity: 1,990 – #26 most on list
> Percent occupied: 118% – #15 highest on list
> County: Madera

Courtesy of Miguel O. via Yelp

24. California Health Care Facility – Stockton (CHCF)
> Inmates: 2,360
> Capacity: 2,953 – #9 most on list
> Percent occupied: 80% – #30 highest on list
> County: San Joaquin

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Public Domain / Wikimedia Commons

23. Calipatria State Prison (CAL)
> Inmates: 2,494
> Capacity: 2,308 – #19 most on list
> Percent occupied: 108% – #23 highest on list
> County: Imperial

Courtesy of Jack W. via Yelp

22. High Desert State Prison (HDSP)
> Inmates: 2,518
> Capacity: 2,324 – #17 most on list
> Percent occupied: 108% – #22 highest on list
> County: Lassen

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Ryan Herron / E+ via Getty Images

21. California State Prison, Los Angeles County (LAC)
> Inmates: 2,557
> Capacity: 2,300 – #22 most on list
> Percent occupied: 111% – #20 highest on list
> County: Los Angeles

Courtesy of Centinela State Prison Inmate Family Council via Facebook

20. Centinela State Prison (CEN)
> Inmates: 2,589
> Capacity: 2,308 – #19 most on list
> Percent occupied: 112% – #19 highest on list
> County: Imperial

19. Kern Valley State Prison (KVSP)
> Inmates: 2,694
> Capacity: 2,448 – #15 most on list
> Percent occupied: 110% – #21 highest on list
> County: Kern

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Courtesy of Salinas Valley Inmate Family Council via Facebook

18. Salinas Valley State Prison (SVSP)
> Inmates: 2,900
> Capacity: 2,452 – #14 most on list
> Percent occupied: 118% – #15 highest on list
> County: Monterey

17. RJ Donovan Correctional Facility (RJD)
> Inmates: 2,938
> Capacity: 2,992 – #7 most on list
> Percent occupied: 98% – #25 highest on list
> County: San Diego

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Bill_Dally / iStock via Getty Images

16. Pleasant Valley State Prison (PVSP)
> Inmates: 2,940
> Capacity: 2,308 – #19 most on list
> Percent occupied: 127% – #12 highest on list
> County: Fresno

15. Folsom State Prison (FOL)
> Inmates: 3,023
> Capacity: 2,065 – #25 most on list
> Percent occupied: 146% – #6 highest on list
> County: Sacramento

Courtesy of Carlos V. via Yelp

14. California Rehabilitation Center (CRC)
> Inmates: 3,026
> Capacity: 1,822 – #29 most on list
> Percent occupied: 166% – #1 highest on list
> County: Riverside

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13. Valley State Prison (VSP)
> Inmates: 3,044
> Capacity: 1,961 – #27 most on list
> Percent occupied: 155% – #3 highest on list
> County: Madera

Public Domain / Wikimedia Commons

12. California Men’s Colony (CMC)
> Inmates: 3,161
> Capacity: 3,816 – #1 most on list
> Percent occupied: 83% – #28 highest on list
> County: San Luis Obispo

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11. Ironwood State Prison (ISP)
> Inmates: 3,180
> Capacity: 2,200 – #23 most on list
> Percent occupied: 145% – #7 highest on list
> County: Riverside

10. California State Prison, Corcoran (COR)
> Inmates: 3,284
> Capacity: 3,115 – #5 most on list
> Percent occupied: 105% – #24 highest on list
> County: Kings

9. California State Prison, Solano (SOL)
> Inmates: 3,438
> Capacity: 2,594 – #13 most on list
> Percent occupied: 133% – #9 highest on list
> County: Los Angeles

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Justin Sullivan / Getty Images

8. Mule Creek State Prison (MCSP)
> Inmates: 3,846
> Capacity: 3,284 – #4 most on list
> Percent occupied: 117% – #17 highest on list
> County: Amador

sassy1902 / E+ via Getty Images

7. San Quentin State Prison (SQ)
> Inmates: 3,897
> Capacity: 3,084 – #6 most on list
> Percent occupied: 126% – #13 highest on list
> County: Marin

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Courtesy Wasco State Prison Support Page via Facebook

6. Wasco State Prison (WSP)
> Inmates: 3,951
> Capacity: 2,984 – #8 most on list
> Percent occupied: 132% – #10 highest on list
> County: Kern

5. Sierra Conservation Center (SCC)
> Inmates: 3,956
> Capacity: 3,404 – #3 most on list
> Percent occupied: 116% – #18 highest on list
> County: Tuolumne

Public Domain / Wikimedia Commons

4. North Kern State Prison (NKSP)
> Inmates: 4,153
> Capacity: 2,694 – #12 most on list
> Percent occupied: 154% – #4 highest on list
> County: Kern

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3. Correctional Training Facility (CTF)
> Inmates: 4,265
> Capacity: 2,800 – #11 most on list
> Percent occupied: 152% – #5 highest on list
> County: Monterey

2. California Substance Abuse Treatment Facility (SATF)
> Inmates: 4,535
> Capacity: 3,424 – #2 most on list
> Percent occupied: 132% – #10 highest on list
> County: Kings

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Courtesy of CACorrections via Facebook

1. Avenal State Prison (ASP)
> Inmates: 4,612
> Capacity: 2,909 – #10 most on list
> Percent occupied: 159% – #2 highest on list
> County: Kings

Methodology

To identify the biggest prisons in California and how crowded they are, 24/7 Wall St. reviewed inmate counts in 32 of the state’s adult correctional institutions. Data is as of March 1, 2023, as California Department of Corrections and Rehabilitation Division of Correctional Policy Research and Internal Oversight Office of Research.

Inmate counts include felons, county contract boarders, federal boarders, state boarders,

safekeepers, county diagnostic cases, Department of Mental Health boarders, and Division of

Juvenile Justice boarders confined in state-run prisons. Each prison’s total capacity and occupancy also came from the California Department of Corrections and Rehabilitation.

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