The Holliston Police Department employs the NextGen 9-1-1 system.
The Massachusetts State 911 Department states, "The Next Generation 911 or “NextGen 911” system depends on high quality mapping: maps of emergency service zone boundaries, maps of address locations as points, and maps of roads. In the NextGen system, location information determines where the call is answered: for cell calls, longitude/latitude or an approximate location based on which cell towers receive the call signal; for landline phones, the addresses. When combined with an Emergency Service Zones (ESZs) boundary map, call locations will be used to route calls to the correct dispatch center. In the dispatch center, the call is displayed with a map to assist in verifying the location of callers; this map includes address locations as points. MassGIS has completed mapping the emergency service zones and draft mapping of address points and their address assignment for every community in the Commonwealth."