The Defense Department said this is the first option year of a previously awarded firm-fixed-price contract.
Northrop will support the Marine Corps’ network operations and security center, which operates the Marine’s global enterprise network for command and control capabilities.
Northrop will perform 91 percent of the work in Quantico, Va. and the rest in Camp Pendleton, Calif.
The Pentagon expects Northrop to complete work in March 2013.
The Marine Corps Systems Command in Quantico is the contracting activity.