In March and April 2020, Cook County Jail emerged as one of the most severe COVID-19 outbreak sites in the United States. At the peak, the jail — which housed over 5,700 people in close quarters — recorded more than 350 confirmed cases among detainees and staff in a matter of weeks. The New York Times and other outlets identified the facility as a leading cluster in national tracking data.
How the Outbreak Unfolded
The first confirmed COVID-19 case in the jail appeared in mid-March 2020. Within days, the infection was spreading rapidly across housing divisions. The jail's population density — dormitory-style units where social distancing was physically impossible — accelerated transmission. By early April, Cook County Jail had more confirmed COVID cases than any other single location in Illinois.
Detainees and their attorneys reported inadequate access to masks, cleaning supplies, and medical information in the early weeks. Several detainees died from COVID-related complications. Staff infection rates were also high, compounding the crisis by reducing the number of correctional officers available.
The Federal Lawsuit: Mays v. Dart
The ACLU of Illinois filed suit in federal court (Mays v. Dart, N.D. Ill. 2020) arguing the jail's conditions violated the constitutional rights of pretrial detainees. Judge Matthew Kennelly issued a preliminary injunction in April 2020 requiring the Sheriff to implement specific infection-control measures: mandatory masking, increased cleaning, improved medical screening, and review of detention for medically vulnerable individuals.
The case was significant because it established in real time that jails have a constitutional obligation to protect detainees from a known infectious disease risk — not just after deaths, but proactively.
Reforms and Changes Post-2020
In response to the lawsuit and to public pressure, Cook County Jail made several lasting operational changes:
- Expanded use of telehealth and remote medical screening to reduce congregate medical line-ups.
- Built out isolation and quarantine capacity inside the facility.
- Accelerated review of medical-vulnerability cases for release or alternative supervision.
- Increased transparency through more regular public reporting on health conditions.
The SAFE-T Act's bail elimination (2023) further reduced the population, lowering density and making some infection-control measures more feasible structurally.