Loudoun County, with an area of 519 square miles, was formed in 1757 from Fairfax and named for Lord Loudoun, titular governor of Virginia and head of the British forces in America from 1756 to 1758. Oak Hill, the home of President James Monroe, is in Loudoun County. Prince William County, with an area of 345 square miles, was formed in 1730 from Stafford and King George and named for William Augustus, Duke of Cumberland, second son of King George II. The First and Second battles of Manassas took place in Prince William County.