Nationwide Survey of Control Units

One of the things that came out of the Unlock the Box conference in 2005 was the need to expand the exchange of information between prisoners and their supporters in both directions. The newsletter, Under Lock & Key is an example of providing a voice for prisoners and a forum for prisoners and activists on the outside to share information, campaign ideas and strategies. Participating organizations' extensive network of contacts in prisons is also a great resource for answering a lot of the questions people have about what is really going on.

One of the research projects initiated from this is the tallying of control units throughout the united states, how many people are held in them, who is in them, and how they are expanding. Most of the statistics to date are around 20 to 25,000 people in Supermax prisons. Recent articles are still stating the 20,000 number published in 1998. The year 2000 U.S. census data shows over 25,000 prisoners in just 25 "Supermax" prisons in 18 states. This is based on prisons that are self-described as "Supermax" and supermax only. This list does not include any prisons in New York State, in which we have documented 44 different prisons with Special Housing Units (SHU) or S-Block, almost all of which were built in the 1990s.

20,0001998Roy D. King
27,3432000U.S. Census
25,7572003American Correctional Association
25,0002004Daniel P. Mears
90,000+2008our own research

In our preliminary survey of public records, and individuals with regional knowledge on control units, we have come up with a list of prisons with an estimated population in long-term isolation of 90,000+. But there are still gaps in our data. We still need numbers for some prisons and even whole states. Some prisons on our list are not of confirmed status. We welcome your input on completing this data, which will continue to be updated online, here at

Contributing Data

If you have data to contribute to this project, please send all relevant information with sources to MIM(Prisons).

Questionnaire sent to Prisoners

As part of our ongoing campaign to Unlock the Box, comrades are updating and completing existing data on control units across the united $tates. To participate in this project please complete this survey and return to:

      ATTN: Unlock the Box Survey
      PO Box 40799
      San Francisco, CA 94140

Control units may vary from prison to prison but they can be generally characterized as: Permanently designated prisons or cells in prisons that lock prisoners up in solitary or small group confinement for 22 or more hours a day with no congregate dining, exercise or other services, and virtually no programs for prisoners. Prisoners are placed in control units for extended periods of time.

Please make a list of all the Control Units that you know of using the definition above. For each prison, separately indicate:

  • Address/location?
  • How many people are in isolation at this prison?
  • What year did the control unit in this prison open?
  • What is the total population at this prison?
  • What is the total capacity of this prison?
  • What year did this prison open?
  • What year did the control unit open?
  • Is the whole prison a control unit, or only certain units? if so, which units and how big are they?
  • What is the name of the control units/isolation in this prison? (i.e. security housing units)
  • What is the national/racial make up of the population in the CU? ie. what percent is Black, Latino, white, etc.?
  • What reasons are given for putting people in the CU?
  • Is the state planning to open any new control units that you know of?
  • Is there anything else you think we should know about the control units in your state?
  • What is your source for this data? (i.e. you were in this control unit in 2013, your brother is held there, you are there now, etc.)
  • Year this data was collected?