Which organization operates military post offices under the jurisdiction of postmasters in major cities?

The organization that operates military post offices under the jurisdiction of postmasters in major cities is the Department of Defense (DoD). The DoD oversees the operations of military mail, including the establishment of postal services specifically for military personnel and their families. These military post offices are integral to ensuring that service members can communicate with loved ones and receive necessary supplies while stationed domestically or overseas.

While the U.S. Postal Service (USPS) provides the logistical framework and delivery services in the civilian sector, military post offices are distinct entities specifically designed to cater to the needs of the armed forces. The USPS may collaborate with the DoD in this regard, but it does not directly operate these military post offices. Federal Express (FedEx) and the American Postal Workers Union (APWU) are not responsible for military mail operations, making them irrelevant in the context of this question.