The Fairfax Stone became the guiding point to future land issues, and ultimately helped determine the boundary of Maryland. The marker was also used in the determination of boundaries between Virginia and West Virginia. Contention concerning the stone and boundaries continued to play out in the court system. Finally in 1912 the U.S. Supreme Court made a ruling defining the West Virginia-Maryland border at the south bank of the North Branch of the Potomac River.
Weather and vandals have made it necessary to replace the stone at least four times. In 1859 Lieutenant Nathaniel Michler resurveyed the area and reported that the stone was deteriorating. By 1883 it had disappeared. Subsequent replacement stones were destroyed, damaged, or removed. The most recent one was placed in 1957. That same year Fairfax Stone Historical Monument State Park was established when the Western Maryland Railroad gave four acres of land surrounding the stone to West Virginia. In 1970, the Fairfax Stone was listed on the National Register of Historic Places. The park is located about six miles north of Thomas, West Virginia, and contains no facilities.