The City of Martinsburg is the county seat of Berkeley County and the largest city in the Eastern Panhandle. A railroad center, Martinsburg is known today as the location of one of the two Enterprise Computing Centers of the Internal Revenue Service. It is also the burial site of Major League Baseball Hall of Famer Hack Wilson, who began his professional career in Martinsburg. HGI has two locations in Martinsburg, at 100 Eagle School Road and in the Spring Mills Shopping Center.