Virginia, officially the Commonwealth of Virginia, is a state in the Southeastern and Mid-Atlantic regions of the United States between the Atlantic Coast and the Appalachian Mountains. It borders Kentucky to the west, Tennessee to the south-west, North Carolina to the south, West Virginia to the north-west, and Maryland to the north. The state's capital is Richmond and its most populous city is Virginia Beach. With a population of 8.8 million, it is the 12th-most populous and 15th-most densely populated state. More than one-third of Virginia's population lives in Northern Virginia, which includes the most populous jurisdiction in the state, Fairfax County.