Vacant lots, when left untended, become liabilities for communities with consequences for crime and violence, including firearm violence. In many urban centers, high vacancies contribute to increased rates of violence and injury, including assaults, robbery, and homicide. A growing body of evidence suggests that remediating and improving vacant lots is a promising strategy to reduce violent crime and firearm assaults. Researchers have also shown that community engagement in efforts to improve vacant lots may be a critical component to sustain efforts and improve violence reduction outcomes. Yet, researchers have examined a relatively narrow range of greening strategies including simple lot remediation (e.g., removing trash & debris) and installation of small-scale lot treatments (e.g., planting trees, installing split rail fencing), and have largely not explored the effect of engaging residents in this process. Further, there is a lack of research on how these efforts are sustained over time and whether continued activation provides additional benefit. The purpose of this study will be to examine crime incidents occurring near vacant lot reuse project sites in Indianapolis, Indiana, where community-based organizations have reclaimed vacant lots for productive purposes. In partnership with Keep Indianapolis Beautiful, we will examine 120 project sites across the city from their inception to up to 5 years post intervention. We will test the hypothesis that vacant lot reuse is an effective strategy for prevention of violence and compare the effects of vacant lot reuse on violent incidents and injury over time relative to a set of comparison sites (N = 240) where no reuse occurs. We will also examine how the level of community engagement may enhance the effects of vacant lot reuse on violence through rigorous site documentation and tracking, as well as case studies of successful community engaged project sites with a reduction in violent incidents. Our specific aims for the proposed research are to: 1) Examine the short term effect of vacant lot reuse projects on total violent crime incidents and injury and how the level of community engagement modifies the effect; 2) Examine the long term effect of vacant lot reuse projects on total violent crime incidents and injury in the short term and how the level of community engagement modifies the effect; and 3) Conduct in-depth case studies of 12 vacant lot reuse sites and their effect on violent crime outcomes and community engagement to identify facilitating factors and barriers to effective reuse.