Giles County was formed on 1st May 1806 by an act of the general assembly that passed on 16 January 1806:

"Be it enacted by the general assembly, That all that part of the counties of Montgomery, Monroe and Tazewell, contained within the following boundaries, to wit: Beginning at the end of Gauly mountain on New River where the counties of Greenbrier and Kanawha intersect; thence up the river with the Greenbrier and Montgomery line to the intersection of Monroe line; thence with the Monroe and Montgomery line to the upper end of Pine's plantation; thence a straight line to the mouth of Rich Creek, leaving the plantation of Hugh Caperton on the right; thence with the Montgomery and Monroe line to the intersection of Botetourt county line, and with the Botetourt and Montgomery line to the top of Gap mountain; thence along the top of said mountain to New River, crossing the same to the end of Walker's creek mountain; thence along the top of said mountain to the intersection of Wythe county line; thence north-westward with said line to the intersection of Tazewell line, and with the Tazewell and Montgomery line to the top of Wolf Creek mountain; thence along Wolf creek mountain to a path leading from the Round Bottom to Harman's mill, about three miles below the mouth of the Clear Fork of Wolf creek; thence a straight line to the Big Spring on East river; thence a straight line to the mouth of Militin's Fork; thence a direct line to the head of Crane creek on the top of the Flat-top mountain; thence a direct line to the three forks of Guyandotte river; thence down said river until it intersects Kanawha county line; thence with the said line to the beginning, shall, from and after the first day of May next, form one distinct county, and be called and known by the name of Giles County."

"The justices...shall meet at the house of George Paris in the said county..."

Samuel Shepherd, The Statutes at Large of Virginia, Vol 3, pp.244-245.