It determined the proprietorship and boundaries of a large tract of mostly unsurveyed land in the British colonies of Maryland and Virginia.

[5] A 1746 survey by Colonel Peter Jefferson (Thomas Jefferson's father) and Thomas Lewis resulted in both the placement of the Fairfax Stone as well as the establishment of a line of demarcation known as the "Fairfax Line", extending from the Stone to the south-east and ending at the source of the Rappahannock River,[6] a distance of 77 miles (124 km).

Their job was to establish the northernmost boundary of Lord Fairfax's land and estate, on the present day borders of Maryland and West Virginia.

[9] The original Fairfax Stone, in accordance with common surveying practices of the era, was most likely simply a natural, unmarked rock selected from among the outcroppings in the area.

Legal boundary disputes between Maryland and Virginia caused the latter to relocate the stone in 1833 after the site had been lost to memory.