MCO 5110.4B - Marine Corps Postal Affairs and Official Mail Program

Scope

MCO 5110.4B establishes policy, assigns responsibilities, and prescribes guidance governing Marine Corps Military Post Offices, Unit Mailrooms, and Official Mail Centers. The order covers postal affairs and the Marine Corps Official Mail Program end to end, appointments, training, mail security, official mail authorization, and deployment mail routing. The IGMC postal functional area inspects directly against its chapters.

Audience

• Unit Mail Officers and assistants appointed in writing to supervise the UMR.
• Unit Mail Clerks and Mail Orderlies appointed by DD Form 2260 and DD Form 285.
• Postal Officers, MOS 0161, running MPO operations.
• Commanders owning the appointments, the official mail authorizations, and the inspection results.

Chapter map

• Chapter 1. Responsibilities. Commanders appoint a primary Unit Mail Officer and assistants in writing, provide space, equipment, and networked computer access for the Directory Service Program, and clerks complete the Mail Clerk Indoctrination Course within 30 days of assuming duties.
• Chapter 3. Unit Mailroom operations. The heart of the order for units.
• Chapter 5. Official Mail Centers, postage stock audits, and expenditure reporting.

Operative content

• Appointments. Two Unit Mail Clerks or Orderlies minimum per unit. The clerk physically retains a DD Form 285 while performing duties, and the DD Form 285 annotates the mail types the appointee handles. Mail Officers complete the indoctrination course within 90 days of appointment. Appointment, support, and revocation documents retain two years.
• Security. UMR entry limits to authorized personnel with a DD Form 1115 no-admittance sign at the entrance. Keys ride a control log, return daily, and never stay with a clerk overnight. Mail transports in a closed-body government vehicle, POVs are not authorized without temporary written authorization.
• Handling. Back stamp all mail on receipt, deliver personal mail only to the addressee, pick up daily, hold nothing past 24 hours without documentation, and keep the daily delivery receipt log one year.
• Official mail. The commander designates in writing who receipts and opens official mail, signed by the current CO with sample signatures, by-direction signature not authorized, and mail clerks are not eligible. Official mail does not open in the UMR.
• Deployment. The Unit Mail Officer submits the mail routing request to the serving MPO 30 days before deployment, the MPO issues the deployed address no earlier than 20 days out.

Connection to higher policy

• DODI 4525.09. The DoD Military Postal Service instruction this order implements.
• DoD Postal Manual and the USPS Domestic Mail Manual. The mail-handling floor.
• 39 USC. Penalty mail statute behind the official mail rules.

Connection to Marine Corps doctrine and lower policy

• MCO 5110.5D. The official mail address listing.
• Installation postal orders and the unit mail handling order, both required UMR publications alongside this order.

Status

Active. Effective 2021-12-09, supersedes MCO 5110.4A and MCO 5110.6C. The portal's earlier 5110.2 entry retired into this one and the alias remains for back-compat.