March 2007

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The Prisons point datalayer shows the location of all correctional facilities (state, county and federal) in Massachusetts that house inmates. Physical locations were verified from the Web site of the Massachusetts Department of Correction, (MA DOC), and written or verbal communication with more than half of the facilities. Facility populations were determined using the MA DOC Count Sheet as of August 14, 2006 and Federal Bureau of Prisons Web site as of Feb. 1, 2007. Ancilary support facilities - treatment centers, process divisions, resource centers, etc. - are not included because there were no inmates living at these facilities.

This layer was modified from its previous version, which was developed by the Massachusetts Department of Environmental Protection’s (DEP) GIS Program based on database information provided by the Criminal History Systems Board (CHSB) (the state agency responsible for maintaining the Commonwealth's criminal justice information system), part of the Massachusetts Executive Office of Public Safety (EOPS). The EOPS is also the parent agency for the MA DOC, which operates the Commonwealth's prison system.

The layer is named PRISONS_PT.


The previous version of the data was compared to the latest lists of facilities using ArcGIS. Closed facilities were removed. MassGIS staff used the Color Ortho Images (2005) to verify the locations of all points. All location documentation items are now stored in the point attribute table; previously these items were stored in the separate PRISONS_PT_LDT table.


The Prisons datalayer's point attribute table contains the following items:
PRISON_ID Unique identifier assigned by MassGIS
Facility name according to Mass. Department of Correction or Federal Bureau of Prisons
Facility address according to Mass. Department of Correction or Federal Bureau of Prisons

City or town in which facility is located

ZIP Code in which the facility is located
Facility mailing address according to Mass. Department of Correction or Federal Bureau of Prisons

Jurisdiction of facility:
  C = County
  S = State
  F = Federal

Sex of inmates

House of Correction (county) or prison (state & federal) inmate actual population

Jail (county) inmate actual population

Design capacity of inmates

Facility security level:
  Max = Maximum
  Med = Medium
  Min = Minimum
  Pre = Pre-release
  AT = Awaiting Trial
L_BASE Base map type code
  DOQ - Digitized on screen using digital orthophoto quad base map
L_ACC_EST Location horizontal accuracy estimate measurement (in feet)
L_TYPE Location type code
  CB - Approximate center of a building footprint positively associated with the facility/site
  CF - Approximate center of a facility
L_METH Location method code
  IN - Interpolation based on primary source material (L_SRC_1)
L_SRC_1 Primary source material code
  AP_DOQ - MassGIS 1:5,000 digital imagery
L_SRC_2 Secondary source material code
  KNOW -  Located by staff through knowledge gained in the course of their professional activities
  MS_WWW - Internet map source
  VERB -  Verbal information
L_SRC_3 Tertiary source material code


MassGIS maintains this datalayer. One facility - Bridgewater State Hospital - is part of this layer and not the Hospitals layer because in all cases, the patients that are admitted to this facility may be charged with or convicted of crimes ranging from misdemeanors to major felonies.

Last Updated 3/2/2007