Such policies are often adopted without considering their effects on an already exhausted criminal justice resource, namely prisons. Using a common pool resource approach ordinarily employed in economic and biological research to investigate the potential depletion of resources held in common, the authors examined the use of and estimated actual needs for prison space by county-level sentencing authorities in a southwestern State. Substantial variation was observed in the way counties used prison space. Some preferred to overuse prison for violent offenders, while others preferred to overuse prison for repetitive offenders. Results indicated the actions of a few jurisdictions within the State significantly affected the overuse of prison as a sentencing alternative. The significance of these findings for future research and potential policy alternatives to incorporate the concept of prison as a common pool resource are discussed. 45 references, 12 notes, and 8 tables