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United States · California · San Quentin
San Quentin State Prison (Sq)
State prisonMaximumOvercrowded (129%)ModerateHigh
Verified
Fresh · 2mo ago
Sources last reviewed on
Data is aggregated from public sources and may be incomplete or out of date. Always verify with primary sources before acting on any figure. See data sources.
For families
How to send mail, money, and visit San Quentin State Prison (Sq)
Step-by-step guidance using the United States system — addresses, money services, visit booking, what to bring on your first visit.
San Quentin State Prison (Sq) is a state prison located in Marin County, California. Rated capacity: 3,082. Reported population: 3,989. Security level: Maximum. Data sourced from the HIFLD Prison Boundaries open dataset.
Capacity
3,082
Current population
3,989
Occupancy
129%
Year opened
—
Operational
Figures from official sources · verified 2 Jun 2026 · methodology
Facility profile
Population held
Mixed/unknown
Opened
—
Region
California
Security level
Maximum
Death-row facility
No
Conditions
No conditions summary available yet.
Visiting
No visiting information available.
Mailing
No mailing information available.
Practical info
Contact the operator's website for inmate-specific procedures.
Known issues
No major issues documented in our database.
Notable inmates
Richard Ramirez1960–2013 · serial killerRicardo Leyva Muñoz Ramirez (; February 29, 1960 â June 7, 2013), better known as Richard Ramirez, was an American serial killer, sex offender and burglar whose killing spree occurred in Greater Los Angeles and the San Francisco Bay Area in the state of California.
Scott Erskine1962–2020 · serial killerScott Thomas Erskine (December 22, 1962 â July 3, 2020) was an American serial killer on California's death row, convicted in 2003 for the 1993 murder of two California boys.
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Manuel Machado Alvarez1960–2020 · criminalManuel Machado Alvarez (1960 â July 3, 2020) was a Cuban murderer who was sentenced to death in California.
Elizabeth Ann Duncan1904–1962Elizabeth Ann Duncan (born Hazel Lucille Sinclaira Nigh; April 16, 1904 â August 8, 1962) was an American murderer.
Source: Wikidata + Wikipedia.
Contact & address
Conditions Risk Score
Derived signal — not a judgement. How it's calculated
18/100
Moderate concern18/100
- Overcrowding
- 12/30
- Oversight reports
- 1/30
- Structural flags
- 0/15
- Death signals
- 5/15
- Conditions text
- 0/10
What the score is responding to:
- · Operating at 129% of design capacity
- · 2 oversight reports in the last 5 years
- · In-custody-death signal in sources
This facility scores 18. The national average across 7,437 scored United States facilities is 2 — 16 points above national average.
Related facilities
Same country, matched on type + security level where possible.
- Woodman State JailGatesvilleMaximumState prison720% occupancy
- Centinela State Prison (Cen)ImperialMaximumState prison150% occupancy
- Kern Valley State Prison (Kvsp)DelanoMaximumState prison152% occupancy
- Diagnostic And Evaluation CenterLincolnMaximumState prison178% occupancy
- High Desert State Prison (Hdsp)SusanvilleMaximumState prison152% occupancy
- Calipatria State Prison (Cal)CalipatriaMaximumState prison161% occupancy
Compared to other facilities in United States
7436 peersConditions risk scorethis: 12/100 · peers avg: 2/100 (+419%)
Higher risk than 92% of peer facilities in United States.
Occupancythis: 129% · peers avg: 93% (+39%)
Capacity (beds)this: 3082 · peers avg: 547 (+464%)
Reports
- marshall-project2 Sept 2022
:00 a.m. EDT 09.02.2022 Life Inside My Wild and Winding Path to a College Degree Behind Bars Rahsaan “New York” Thomas was proud to finally earn his associate’s degree in San Quentin State Prison. But repeated COVID-19 lockdowns turned his graduation ceremony into a two-year ordeal. Douglas Lopes for The Marshall Project As a kid, I didn’t see the value of education. My mother sent my brother and
- marshall-project18 Mar 2022
Project Douglas Ray Stankewitz is California’s longest-serving death-row prisoner. The 63-year-old Monache and Cherokee Indian from the Big Sandy Rancheria has spent 43 years in San Quentin State Prison for a crime he says he didn’t commit: the Feb. 8, 1978 carjacking and murder of 21-year-old Theresa Graybeal in Fresno, California. (Stankewitz says that while he was in the group of young people
- marshall-project13 Apr 2021
entity, history, family or community. The word choice reinforced the very trope the story attempted to challenge. I know that journalists can do better because I’m one myself. At San Quentin State Prison, where I am serving multiple life sentences, I serve as the chairman of a satellite chapter of the Society of Professional Journalists for Northern California (SQ-SPJ). I also co-host the
- marshall-project17 Dec 2019
er scale. At Green Haven and Fishkill Correctional Facilities in New York, I watched theatrical performances by incarcerated men sponsored by Rehabilitation Through the Arts . At San Quentin State Prison in California, I met with the prison newspaper’s staff and attended a finance class led by a self-taught instructor serving a life sentence. While visiting the Osborne Association’s parenting
Data completeness
74%How many of our profile fields are populated. We surface this so families and researchers know the limits.
Sources
- HIFLD Prison Boundaries
- HIFLD dataset query
- HIFLD Prison Boundaries — US Department of Homeland Security â HIFLD Open Data
- See /data-sources for our overall methodology.
Cite this page
Under CC-BY-4.0. Include the URL and access date; the site is a living reference and entries can change.
APA
World Prisons. (2026). San Quentin State Prison (Sq). Retrieved July 21, 2026, from https://worldprisons.com/prisons/san-quentin-state-prison-sq
Chicago
"San Quentin State Prison (Sq)." World Prisons. Accessed July 21, 2026. https://worldprisons.com/prisons/san-quentin-state-prison-sq.
BibTeX
@misc{worldprisons-san-quentin-state-prison-sq,
author = {{World Prisons}},
title = {San Quentin State Prison (Sq)},
year = {2026},
url = {https://worldprisons.com/prisons/san-quentin-state-prison-sq},
urldate = {2026-07-21}
}