Although crime statistics, and in some cases static maps, have been available to the public via the Web for several years, the 35 participating agencies of the Automated Regional Justice Information System (ARJIS) recognize the effectiveness of the Web to disseminate crime information through an interactive mapping application. The development of such an application displaying crimes and arrests from a regional repository and calls for service from individual CAD systems in near real time is becoming a reality for San Diego County. This paper will discuss the processes associated with developing an interactive crime mapping application available on the Web.