Leesburg is a historic town within and the county seat of Loudoun County, Virginia. Leesburg is 33 miles (53 km) west-northwest of Washington, D.C. along the base of Catoctin Mountain and adjacent to the Potomac River. Its population according to the 2016 United States Census is 52,607.  The town is also the northwestern terminus of the Dulles Greenway, a private toll road that connects to the Dulles Toll Road at Washington Dulles International Airport.
Leesburg, like the rest of Loudoun, has undergone considerable growth and development over the last 30 years, transforming from a small, rural, piedmont town to a suburban bedroom community for commuters to the national capital. Growth in the town and its immediate area to the east (Lansdowne/Ashburn) concentrates along the Dulles Greenway and State Route 7, which roughly parallels the Potomac River between Winchester to the west and Alexandria to the east.
The Federal Aviation Administration's Washington Air Route Traffic Control Center is in Leesburg.
Leesburg was named to honor the influential Thomas Lee and not, as is popular belief, his son Francis Lightfoot Lee who lived in Loudoun and brought up the bill to establish Leesburg, nor as is sometimes thought, Robert E. Lee (his great-grandnephew).
Prior to European settlement, the area around Leesburg was occupied by various Native American tribes. John Lederer (1670) testified that the entire Piedmont region had once been occupied by the "Tacci, alias Dogi", but that the Siouan tribes, driven from the northwest, had occupied it for 400 years.