SR 7 exits the city into surrounding Frederick County, where its name changes to Berryville Pike and it becomes a four-lane highway.

SR 7 crosses the Shenandoah River and its name changes to the Harry Flood Byrd Highway.

SR 7 crosses the Loudoun–Clarke county line and the Appalachian Trail at the summit of Snickers Gap in the Blue Ridge Mountains.

SR 7 descends out of the Blue Ridge Mountains and enters the rural western area of Loudoun County as Leesburg Pike at Snickers Gap.

SR 7 continues towards the well-developed eastern half of Loudoun County as a four-lane divided highway with some at-grade intersections, and it passes through Clarke's Gap in Catoctin Mountain.

In addition to widening Westbound SR 7 from two to three lanes, the median was modified to limit left turns into and out of Roxbury Hall Road, Leeland Orchard Road, White Gate Place, and Beechnut Place.

The southern roundabout combined the separate intersections of the on and off ramps from SR 7 and Colonial Highway/Dry Mill Road into one.

To accomplish this, highway interchanges were constructed replacing the ordinary intersections at Belmont Ridge Road, Claiborne Parkway, Ashburn Village Boulevard, and Loudoun County Parkway while closing the intersection at Lexington Drive.

A new overpass was constructed to carry Sycolin Road across SR 7 in Leesburg, which opened to traffic on August 11, 2014.

SR 7 is named Leesburg Pike all the way across Fairfax County, where it is mainly a suburban route.

It continues through Fairfax County, passing by subdivisions in unincorporated Great Falls, Vienna, and Reston.

SR 7 then re-enters Fairfax County as Leesburg Pike and passes through Seven Corners, named for the five roads that intersect, including SR 338 (Hillwood Avenue) and US 50 (Arlington Boulevard), which is grade separated from the rest of the intersection.

It continues as King Street through Alexandria, passing by Alexandria City High School, George Washington Masonic National Memorial, Union Station (Amtrak and Virginia Railway Express), and the King Street–Old Town Metro station.

On August 19, 2019, a third left-turn lane was added from SR 7 west to Baron Cameron Avenue.

[10] This was in place of constructing a partial interchange at the intersection, for which SR 7 east lanes would travel under Baron Cameron Avenue; the project was never started, as VDOT failed to allocate sufficient funding for the project and lack of competition led to higher than forecasted bids for the Route 7 widening.

This is in an effort to restore historical names and remove segregationist and Confederate symbols throughout the county.