MSAG (Master Street Address Guide)

MSAG (Master Street Address Guide) is a database of street names and house number ranges within their associated communities defining Emergency Service Zones (ESZs) and their associated Emergency Service Numbers (ESNs) to enable proper routing of 9‑1‑1 calls.

MSAG Address

An address recognized by Public Safety for the dispatch of emergency first responders. It is an absolute and unique address in that variants for directions, street spelling, street suffixes, and community names are not allowed. It is preferred that MSAG Addresses be in Civic Address format.

MSAG Baseline

An MSAG file that is a snapshot image which represents a complete, up-to-date set of MSAG data at the point in time it was created.

MSAG Consumer

Identifies appropriate organizational entities that have an accepted need for the MSAG in order to support E9-1-1 (e.g., DBMSPs, SPs, Wireless, VDBs, ERDBs, VSPs).

MSAG Coordinator, MSAG Administrator

The individual with the 9‑1‑1 Governing Authority or 9‑1‑1 Authority who has responsibility for all daily maintenance of the 9‑1‑1 database, to include, but not limited to MSAG maintenance, 9‑1‑1 Inquiry resolution, notifying Service Providers of address changes or corrections for a resident.

MSAG Delta

A file of incremental changes to the MSAG. The changes are applied in the order that they are presented, to either the last updated version of the MSAG or a current Baseline of the MSAG, whichever is more recent.

MSAG Discrepancy

A record being retrieved from ALI during an actual E9-1-1 call with incorrect information because an MSAG field was incorrect. For example, incorrect ESN assignment or transposition of numbers, incorrect house number ranges, odd/even indicator.

MSAG Error

A hard error from DBMS service order processing or a manual update that failed to meet the MSAG specifications.

MSAG Local Operational

An MSAG maintained in a format other than the recommended standard set forth in NENA 02-010 and 02-011. This format may consist of variances to the standard MSAG such as unparsed and concatenated fields for directional, street name, and suffix.

MSAG Operator

Typically, this is the Database Management System Provider who works in conjunction with a 9-1-1 Administrator.

MSAG Source

Represents a recognized supplier of MSAG files, which may be the MSAG Administrator, or an authorized MSAG Operator. The MSAG Source is typically the E9-1-1 System Service Provider, but may be the 9-1-1 Administrator’s MSAG Administrator.

MSAG Standard

An MSAG maintained in accordance with the data fields as recommended in NENA standards.


 * NENA 02-011, NENA Data Standards for Local Exchange Carriers, ALI Service Providers &amp; 9-1-1 Jurisdictions
 * NENA 71-501, NENA Information Document for Synchronizing Geographic Information System databases with MSAG &amp; ALI
 * NENA-STA-010, NENA i3 Standard for Next Generation 9-1-1
 * NENA-STA-015, NENA Standard Data Formats for 9-1-1 Data Exchange &amp; GIS Mapping