Information on the various State mechanisms for reducing prison overcrowding was obtained from telephone interviews with key State officials from November 1981 through January 1982. The targeted States were selected from those identified in resource materials as having implemented the most promising mechanisms. Information is provided on each mechanism's development, legislative enactment, implementation, and assessment. Mechanisms that shorten the average prison stay are categorized as emergency mechanisms and those providing ongoing community reintegration. Emergency mechanisms include sentence rollbacks (Michigan), administrative good time (Illinois), judicial control of prison populations (Connecticut), and use of jails (Oklahoma). Ongoing community reintegration programs include re-entry furloughs (Connecticut), supervised custody (Delaware), supervised furlough (South Carolina), extended work release (South Carolina), and earned work credits (South Carolina). Programs characterized as facing community backlash are work furlough (Arizona) and early parole (Maryland). Sentencing guidelines (Minnesota) and postsentence diversion (Georgia and Virginia) are presented as mechanisms for reducing the number of offenders imprisoned. The authors consider the most promising mechanisms to be judicial authority to control prison populations, ongoing early release programs, the liberal use of good time and work credits, extended work release, sentencing guidelines, and presentence diversion.