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Defense Health Agency

"On October 1, 2013, the Department of Defense established the Defense Health Agency (DHA) to manage the activities of the Military Health System. These activities include those previously managed by TRICARE Management Activity (TMA), which was disestablished on the same date. During the next several months, all TMA websites will change to reflect the new DHA. We appreciate your patience during this transition."

DHA-GL Contact Information

The Defense Health Agency (DHA) – Great Lakes (formerly known as MMSO) (DHA-GL) assists with the coordination of medical care for Remote Active Duty and Remote Reserve Component Service Members on orders for 30 days or less with Service approved line of duty conditions. For enrollment, other active duty, dependent, retiree and all other questions contact your regional Managed Care Support Contractor or click here.

Hours of operation: Monday through Friday, 0800 to 1630, Central time.

Service members receiving treatment for line of duty conditions will not show as eligible for care in the Defense Enrollment Eligibility Reporting System (DEERS). To verify eligibility, contact the service member's unit administrator or medical representative. All claims for line of duty medical care should be submitted to the Managed Care Support Contractor serving the area in which the member lives.

For active duty TRICARE Prime Remote and Remote Reserve Component Line of Duty care questions contact DHA-GL at:

Phone: 1-888-MHS-MMSO (1-888-647-6676) and follow menu prompts.


Defense Health Agency-GL
Suite 304
2834 Green Bay Road
North Chicago, IL 60064-3091