a majority of the acting justices of the peace for the said
county of Fairfax, together with the justices of the county
of Loudoun included within the part thus added to the said
county of Fairfax, and they are hereby required at a court
to be held in the month of April or May next, to fix on a
place for holding courts therein at or as near the center
thereof (having regard to that part of the county of Loudoun
hereby added to the said county of Fairfax) as the situation
and convenience will admit of; and thenceforth proceed to
erect the necessary public buildings at such place, and
until such buildings be completed, to appoint any place for
holding courts as they shall think proper.

3. This act shall commence and be in force from and after
the passing thereof.

As at present bounded, the old channel at the mouth of Sugar Land run,
at Lowe's Island,[3] is "the commencement of the line that separates
Loudoun from Fairfax County and runs directly across the country to a
point on the Bull Run branch of Occoquan River, about three eighths of
a mile above Sudley Springs, in Prince William County." The Bull Run
then forms the boundary between Loudoun and Prince William to its
highest spring head in the Bull Run mountain, just below the Cool
Spring Gap. The line then extends to the summit of the mountain, where
the counties of Fauquier and Prince William corner. From the summit of
this mountain, a direct line to a point[4] on the Blue Ridge, at
Ashby's Gap, marks the boundary between Loudoun and Fauquier counties.
A devious line, which follows in part the crests of the Blue Ridge
until reaching the Potomac below Harpers Ferry, separates Loudoun from
Clarke County, Virginia, and Jefferson County, West Virginia, on her