Prisoners originate most-heavily from areas with high poverty rates, as the graphic above shows. Each dot in the graphic represents the home address of a prisoner committed to state prison.
The concentration of prisoners in poverty areas closely tracks the concentration of crime in those areas. The graphic below compares the concentration of state prisoners sentenced for assault offenses to medical reports of shootings and stabbings.
Source for charts: Profile of Anti-drug Law Enforcement in Urban Poverty Areas in Massachusetts. Brownsberger, 1997.