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Alton Military Prison
State prisonFirst Illinois state penitentiary and Union prisonClosed 1865Medium
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Data is aggregated from public sources and may be incomplete or out of date.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 Alton Military Prison
Step-by-step guidance using the United States system — addresses, money services, visit booking, what to bring on your first visit.
Gallery
From Wikimedia Commons (CC-BY-SA where not otherwise stated).
Photo by Unknown authorUnknown author via Wikimedia Commons (Public domain)
Photo by Nyttend via Wikimedia Commons (Public domain)
Photo by Mook, George J. via Wikimedia Commons (Public domain)
Photo by Mook, George J. via Wikimedia Commons (Public domain)
Photo by Sandidge, P.S. via Wikimedia Commons (Public domain)
Background
The Alton Military Prison was a prison located in Alton, Illinois, built in 1833 as the first state penitentiary in Illinois and closed in 1857. During the American Civil War, the prison was reopened in 1862 to accommodate the growing population of Confederate prisoners of war and ceased to be prison at the end of the war in 1865. The prison building was demolished not long after the Civil War. All that remains of the former prison site is a section of ruin wall that is maintained by the State of Illinois as an historic site. The prison site is included in the U.S. National Register of Historic Places.
Source: Wikipedia article lead, CC-BY-SA.
Capacity
1,833
Current population
—
Occupancy
—
Year opened
—
Closed 1865
Figures from official sources · verified 31 May 2026 · methodology
Facility profile
Population held
Mixed/unknown
Opened
—
Region
IL
Security level
First Illinois state penitentiary and Union prison
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
M. Jeff Thompson1826–1876 · engineerBrigadier-General Meriweather Jeff Thompson (January 22, 1826 â September 5, 1876), nicknamed "Swamp Fox," was an American soldier who was a senior officer of the Missouri State Guard who commanded cavalry in the Trans-Mississippi Theater of the American Civil War.
Source: Wikidata + Wikipedia.
Contact & address
Alton, Illinois, United States
No public contact details available.
Conditions Risk Score
Derived signal — not a judgement. How it's calculated
—
Insufficient data
We don't have enough public data on this facility to score it. Have something to add? Send us a correction.
Related facilities
Same country, matched on type + security level where possible.
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- Woodman State JailGatesvilleMaximumState prison720% occupancy
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- Residential Correctional Facility, DavenportDavenportState prison208% occupancy
- Diagnostic And Evaluation CenterLincolnMaximumState prison178% occupancy
Compared to other facilities in United States
7436 peersCapacity (beds)this: 1833 · peers avg: 547 (+235%)
Data completeness
48%How many of our profile fields are populated. We surface this so families and researchers know the limits.
Sources
- Wikipedia — Wikimedia Foundation
- Wikipedia category â Prisons in Illinois — Wikimedia Foundation
- Wikidata — Wikimedia Foundation
- Wikidata (Q16152499)
- Wikipedia
- Wikimedia Commons
- 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). Alton Military Prison. Retrieved July 21, 2026, from https://worldprisons.com/prisons/alton-military-prison
Chicago
"Alton Military Prison." World Prisons. Accessed July 21, 2026. https://worldprisons.com/prisons/alton-military-prison.
BibTeX
@misc{worldprisons-alton-military-prison,
author = {{World Prisons}},
title = {Alton Military Prison},
year = {2026},
url = {https://worldprisons.com/prisons/alton-military-prison},
urldate = {2026-07-21}
}