Northrop Grumman Corp. said it was awarded a task order potentially worth $1.1 billion to enhance and maintain classified networks for the Department of Homeland Security.

The order was awarded by the U.S. General Services Administration, and Northrop's work will be done on a one-year base period with six year-long option periods. Northrop said it will lead work to "sustain and modernize classified enterprise information-technology services" for Homeland Security.

As...