Area Information
As of the 2010 census, the county population was 104,169, making it the second-most populous of West Virginia's 55 counties, behind Kanawha. The City of Martinsburg is the county seat.

History: Most historians believe the county was named for Norborne Berkeley, Baron de Botetourt (1718–1770), Colonial Governor of Virginia from 1768 to 1770.
During the American Revolutionary War (1775–1783), the Mingo and Shawnee, headquartered at Chillicothe, allied themselves with the British. In 1777, a party of 350 Wyandots, Shawnees and Mingos, armed by the British, attacked Fort Henry, near present-day Wheeling. In 1670, John Lederer, a German physician and explorer employed by Sir William Berkeley, colonial governor of Virginia, became the first European to set foot in present-day Berkeley County.
Berkeley County was of strategic importance to both the North and the South during the American Civil War (from 1861 to 1865). The county, and Martinsburg, the county seat, lay at the northern edge of the Shenandoah Valley, and Martinsburg was very important because the main line of the Baltimore and Ohio Railroad ran through the town. The rail line was of great importance to both armies. Also, Martinsburg was close to the Union arsenal at Harpers Ferry. Control over Martinsburg changed hands many times during the war, especially prior to the Battle of Gettysburg in July 1863. After Gettysburg, the city remained mostly under Union control.

Resources: Wikipedia

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