Martinsburg, industrial city (1990 pop. 14,073), seat of Berkeley co., NE W.Va., in the Eastern Panhandle; settled 1732, inc. as a city 1859. It is a railroad center in a region that grows apples and peaches. Manufactures include building materials, glassware, textiles, fiberglass, metal and wood products, modular homes, aircraft parts, and ordnance. Limestone is quarried nearby. In the Civil War the city's strategic location on the railroad made it a frequent military objective. Belle Boyd, the Confederate spy, lived there and was imprisoned in the old courthouse. Nearby Bunker Hill, settled c.1729, is the oldest recorded settlement in the state.