Which of the following best describes the Master Street Address Guide (MSAG)?

• A. Municipal Street Address Guide
• B. Master Street Address Guide
• C. Master Street Address Grid
• D. Master Street Allocation Guide

Answer: (B)

MSAG stands for Master Street Address Guide. It is the official directory used in Enhanced 911 systems that lists every street name and house-number range within a geographic area, paired with the emergency response information for those addresses (which PSAP and responding agencies handle them). When a 911 call comes in, the MSAG is consulted to validate the caller’s address, determine the correct PSAP to route the call to, and guide the dispatch of the appropriate emergency responders. Keeping the MSAG accurate and up-to-date is essential for reliable routing and proper dispatch. This is why the best description is simply the Master Street Address Guide itself.