The City of Manassas is an independent city surrounded by Prince William County and the independent city of Manassas Park in the Commonwealth of Virginia. Its population was 37,821 as of 2010. Manassas also surrounds the 38-acre (150,000 m2) county seat for Prince William County but that county property is not part of the city. Manassas either contains or is close to several important historic sites from the period 1850 - 70. The Bureau of Economic Analysis combines the city of Manassas (along with Manassas Park) with Prince William County for statistical purposes. The City of Manassas is part of the Washington Metropolitan Area and it is situated in the Northern Virginia region.
In July 1861, the First Battle of Manassas – also known as the First Battle of Bull Run – the first major land battle of the American Civil War, was fought near here. Manassas will commemorate the 150th anniversary of First Battle of Manassas July 21–24, 2011.
Second Battle of Manassas (or the Second Battle of Bull Run) was fought near here on August 28–30, 1862. At that time, Manassas Junction was little more than a railroad crossing, but a strategic one, with rails leading to Richmond, Virginia, Washington, D.C., and the Shenandoah Valley. Despite these two Confederate victories, Manassas Junction was in Union hands for most of the war.