It contains address information, including street names, house number ranges, and other location details, which are essential for accurately routing emergency calls and dispatching emergency services. 

• Emergency Call Routing: The MSAG is used to validate street addresses during emergency 911 calls. It helps ensure that calls are routed to the correct emergency dispatch center, known as a Public Safety Answering Point (PSAP).

• Address Verification: The database includes detailed information about streets, including names, address number ranges, community names, and corresponding emergency service numbers (ESNs). This information is used to verify the location of a caller and determine the appropriate emergency response jurisdiction.

• Coordination with GIS: The MSAG is often coordinated with Geographic Information Systems (GIS) to enhance the accuracy of location data. This integration is crucial for systems like Enhanced 911 (E911), which provide automatic location identification.

• Regular Updates: The MSAG is continually updated to reflect new developments, road changes, and annexations to ensure that it remains accurate and comprehensive.

The Master Street Address Guide is a foundational element of the 911 emergency response system in the United States, ensuring that emergency services can be dispatched to the correct location as quickly as possible.