What Makes Idaho Maximum Security Institution (IMSI) Different: Population, Security, and What It Means for Families
IMSI fills a very specific role in Idaho's prison system. Understanding who is housed there and what the security level looks like will help you set realistic expectations for contact, visits, and the rules your family needs to follow.
IMSI houses Idaho's most dangerous and volatile male residents. The population is primarily close custody, which means higher security housing, tighter controls on movement, and more restricted day-to-day routines.
IMSI also houses people in administrative segregation. For families, this matters because segregation settings typically mean stricter supervision and fewer opportunities for normal interaction, even when visits are allowed.
IMSI is also where Idaho houses residents under sentence of death. That status brings a high-security environment, so expect close control of contact and carefully managed visiting procedures.
On top of all that, IMSI operates the state Secure Mental Health Facility, housing residents in the Idaho Security Medical Program (ISMP). This is one more reason the facility's population and daily operations look different from a typical prison unit focused solely on custody.
IMSI opened in November 1989 and has been part of Idaho's prison system for decades. It was designed from the ground up for maximum security housing.
The facility holds up to 535 residents. That number gives you a sense of scale: this is a mid-sized institution with a focused mission, not a large general-population complex.
Note: IMSI is secured by a double perimeter fence reinforced with razor wire and an electronic detection system. That level of security comes with stricter procedures for entry, movement, and visiting.
IMSI operates the state Secure Mental Health Facility, housing residents in the Idaho Security Medical Program (ISMP). In practical terms, IMSI is not only a maximum security prison. It is also where Idaho places certain residents who need care in a secure mental-health setting.
Visits Communications
- ✓ Read the “Visiting Rules for Residents and Visitors” before you try to visit IMSI.
- ✓ Complete the visiting application process before your visit. All potential visitors must submit an application and complete a background check.
Note: Visiting schedules at IMSI can change based on emergency situations. Check the current schedule before you make travel plans.
Idaho Code 18-5210 makes it a crime to knowingly introduce or possess contraband in a correctional facility. Common examples that families sometimes overlook include tobacco, cell phones or other telecommunications equipment, controlled or illegal substances, firearms or other dangerous weapons, ammunition or explosives, and escape tools or devices.
Warning: Violations can mean up to 5 years imprisonment and/or a fine up to $10,000.
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