History and Comprehensive Description of Loudoun County, Virginia | Page 4

and Potomac rivers to their sources was included in this grant, afterwards known as the "Fairfax Patent," and still later as the "Northern Neck of Virginia."
"The only conditions attached to the conveyance of this domain, the equivalent of a principality, were that one-fifth of all the gold and one-tenth of all the silver discovered within its limits should be reserved for the royal use, and that a nominal rent of a few pounds sterling should be paid into the treasury at Jamestown each year. In 1669 the letters patent were surrendered by the existing holders and in their stead new ones were issued.... The terms of these letters required that the whole area included in this magnificent gift should be planted and inhabited by the end of twenty-one years, but in 1688 this provision was revoked by the King as imposing an impracticable condition."[2]
[Footnote 2: Bruce's Economic History of Virginia.]
The patentees, some years afterward, sold the grant to the second Lord Culpeper, to whom it was confirmed by letters patent of King James II, in 1688. From Culpeper the rights and privileges conferred by the original grant descended through his daughter, Catherine, to her son, Lord Thomas Fairfax, Baron of Cameron--a princely heritage for a young man of 20 years.
BOUNDARIES.
The original boundaries of Loudoun County were changed by the following act of the General Assembly, passed January 3, 1798, and entitled "An Act for adding part of the county of Loudoun to the county of Fairfax, and altering the place of holding courts in Fairfax County."
1. Be it enacted by the General Assembly, That all that part of the county of Loudoun lying between the lower boundary thereof, and a line to be drawn from the mouth of Sugar Land run, to Carter's mill, on Bull run, shall be, and is hereby added to and made part of the county of Fairfax: Provided always, That it shall be lawful for the sheriff of the said county of Loudoun to collect and make distress for any public dues or officers fees, which shall remain unpaid by the inhabitants of that part of the said county hereby added to the county of Fairfax, and shall be accountable for the same in like manner as if this act had not been made.
2. And be it further enacted, That it shall be lawful for 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 western border. The Potomac then becomes the dividing line between Loudoun County, and Frederick and Montgomery counties, Maryland; "and that State, claiming the whole of the river, exercises jurisdiction over the islands as well as the river."
[Footnote 3: "What is called Lowe's Island, at the mouth of Sugarland Run, was formerly an island, and made so by that run separating and part of it passing into the river by the present channel, while a part of it entered the river by what is now called the old channel. This old channel is now partially filled up, and only receives the waters of Sugarland Run