Manassas Park is a part of the Washington-Arlington-Alexandria, DC-VA-MD-WV Metropolitan Statistical Area.

During the American Civil War, the Manassas Park area was used as a campsite by the Confederate States Army during both the First and Second Battles of Bull Run.

Manassas Park was created as a subdivision of Prince William County, with the first houses being constructed in 1955.

It is longest NW–SE along Manassas Drive, and is bisected by Virginia State Route 28 at its narrowest section.

According to the United States Census Bureau, the city has a total area of 2.5 square miles (6.5 km2), all of it land.

In June 2021, U.S. News & World Report ranked Manassas Park with the fifth best life expectancy in the United States at 92.5 years old.

From Manassas Park, SR 28 extends north to Interstate 66 and south to Virginia State Route 234, providing connections to major cities through the region.