"Although the pace of criminal justice reform has accelerated at both the federal and state levels in the past decade, current initiatives have had only a modest effect on the size of the prison population. But over this period, three states - New York, New Jersey, and California - have achieved prison population reductions in the range of 25%. They have also seen their crime rates generally decline at a faster pace than the national average" (p. 1). This brief describes how these outcomes were achieved and explains other states can significantly reduce their prison population while ensuring public safety. Sections contained in this brief are: key findings; a decade of evolving criminal justice reform; limited impact on incarceration to date; substantial prison population declines in three states; impact of prison populations reductions on crime; policies and practices that reduced the prison population in the three states; the limited relationship between incarceration and crime; international experience in prison population reduction; potential for substantial prison population reductions; three goals for expanding prison population reduction; and conclusion.