The standardized structure of the FBI’s National Incident-based Reporting System (NIBRS) data transcends the needs of a single law enforcement agency. Neighboring agencies can compare like information on emerging crime patterns and problems that extend beyond local law enforcement boundaries. Access to data from neighboring agencies allows cross-jurisdictional problem solving and crime analysis without requiring complicated interagency agreements for collaboration. Data from neighboring communities can then be used to follow and even anticipate trends. Law enforcement’s ability to monitor hot spots of crime and anticipate changes in patterns of offending provides important opportunities for proactive prevention strategies that use scarce resources most effectively. Crime mapping and other analysis techniques for identifying crime patterns over time and location support problem-oriented policing efforts. These efforts are enhance by a well-designed incident-based reporting (IBR) system. While able to monitor growth within its own boundaries, understanding the regional implications can help thwart a rapid expansion across jurisdictions. Routine monitoring of local and regional trends can help identify changes in offending patterns and serve as a multijurisdictional early warning system. This chapter examines how the FBI’s standardized IBR systems; specifically the NIBRS can help surmount several multijurisdictional data-sharing obstacles, demonstrates how the Commonwealth of Massachusetts overcame many barriers to regional crime mapping by enhancing its statewide IBR system; and discusses several data quality issues critical to obtaining reliable results when sharing data among jurisdictions. Tables, figures and references