CA Three Letter IDs

California Three-Letter Designator Request Procedure

Requests must be submitted in writing from the Department Chief to the Cal OES, Fire and Rescue Branch for approval and processing to the attention of: MACS 3 Letter ID Administrator, Cal OES Fire and Rescue Branch at 2524 Mulberry St., Riverside, CA 92501.

2. Request letter must have a signature block for the respective Cal OES Operational Area Coordinator to sign. By signing this letter of request, the Cal OES Operational Area Coordinator is supporting the request and concurs that you meet the following:
  • Must have emergency fire, rescue, and/or hazardous materials response jurisdictional responsibility.
  • The Cal OES Fire and Rescue Operational Area Coordinator and/or the County Fire Chiefs Association recognize agency.
  • Agency participates in the California Fire and Rescue Mutual Aid System.
  • Jurisdiction must be signatory to the State Master Mutual Aid Agreement or a Federal Agency or Tribal Fire Department with fire protection responsibility.
  • Must have a designated Public Safety Answering Point and/or Emergency Communication Dispatch Center.
3. Local jurisdictions contracting with a private contractor/vendor will use the three-letter designator assigned to that jurisdiction.
4. Please indicate first, second and third choice for your three-letter designator in the letter. (You can see which 3 letter IDs are currently in use by clicking here.)
5. You will receive written confirmation of the three-letter designator assigned to your agency or written notice of non-approval on your request. If approved, Operations Bulletin 31 and the Cal OES Form F-5 will be included with the letter of confirmation.
6. Upon approval, you will be directed to submit your agency’s resource information into the California Fire Resources Inventory System (CFRIS) database by completing the Cal OES Form F-5 California Fire and Rescue Mutual Aid System Resources Inventory in the FIRESCOPE website at The Operations Bulletin 31 contains directions on how to submit your agency’s resource information.
7. Before you can enter your resource information you will have to submit a request for a login password. To do this, go to the “Login” menu option in the FIRESCOPE website, click on “Request a FIRESCOPE Login,” and follow the instructions given.
8. Once your login/ID account has been established, go to the FIRESCOPE Website and click on the Login menu option. You will be asked to enter your FIRESCOPE ID, which will be your three-letter designator, along with the Password you have chosen. This will take you to the FIRESCOPE website's Application menu. Your department's Resource inventory can be entered or updated via the "CFRIS" application.
9. Please be sure to keep your agency’s resource information up-to-date at all times.
10. Agencies that do not have the capability to submit their resource information via the Internet are requested to complete the Cal OES Form F-5 and mail it to the same address noted in Number One above.
11. You will also need to apply for your Fire Department Identification (FDID) Number. The contact information is: FDID Program Coordinator of CAL FIRE– Office of the State Fire Marshal at P.O. Box 944246, Sacramento, California 94244-2460, Reception Phone of (916) 445-8200,
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You can contact the MACS 3 Letter ID Administrator at (916) 642-3825 should there be any questions.

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