Beginning from the Atlantic Ocean, the state's eastern border with South Carolina runs up the Savannah River, northwest to its origin at the confluence of the Tugaloo and Seneca Rivers. It then continues up the Tugaloo (originally Tugalo) and into the Chattooga River, its most significant tributary. These bounds were decided in the 1797 Treaty of Beaufort, and tested in the U.S. Supreme Court in the two Georgia v. South Carolina cases in 1923 and 1989.
The border then takes a sharp turn around the tip of Rabun County, at latitude 35°N, though from this point it diverges slightly south (due to inaccuracies in the original survey). This northern border was originally the Georgia and North Carolina border all the way to the Mississippi River, until Tennessee was divided from North Carolina, and the Yazoo companies induced the legislature of Georgia to pass an act, approved by the governor in 1795, to sell the greater part of Georgia's territory presently comprising Alabama and Mississippi.
The state's western border runs in a straight line south-southeastward from a point southwest of Chattanooga, to meet the Chattahoochee River near West Point. It continues downriver to the point where it joins the Flint River (the confluence of the two forming Florida's Apalachicola River); the southern border goes almost due east and very slightly south, in a straight line to the St. Mary's River, which then forms the remainder of the boundary back to the ocean.
The water boundaries are still set to be the original thalweg of the rivers. Since then, several have been inundated by lakes created by dams, including the Apalachicola/Chattahoochee/Flint point now under Lake Seminole.
Georgia state legislators have claimed that in an 1818 survey, the state's border with Tennessee was erroneously placed one mile (1.6 km) farther south than intended, and have continued to dispute this with Tennessee. Correction of this inaccuracy would allow Georgia access to water from the Tennessee River.