Local governments across the United States are striving to improve public safety and optimize criminal justice investments. To support these efforts, the Justice Reinvestment Initiative (JRI) convenes justice system decisionmakers to devise data-driven approaches to criminal justice reform; such approaches generate savings that can be reinvested in evidence-based public safety strategies. This policy brief considers the importance of collaboration with local justice partners in the formulation and implementation of state- level justice reinvestment solutions. It highlights the need to share data to identify and implement cost-saving solutions, partner to promote successful policy implementation, and invest locally.