The power companies filed a merger application Thursday with the Maryland Public Service Commission. They announced the $4.7 billion deal in February.

Akron, Ohio-based FirstEnergy says it would put the regional headquarters somewhere in the Maryland territory served by Allegheny’s Potomac Edison subsidiary. Potomac Edison has about 250,000 Maryland customers in Allegany, Carroll, Frederick, Garrett, Howard, Montgomery and Washington counties.

Allegheny, based in Greensburg, Pa., was headquartered in Hagerstown from 1996 to 2004.

The companies also promise no net reduction in employment of Allegheny Power utilities due to layoffs for at least two years after the merger.