McCaysville is located along the northern border of Fannin County and the state of Georgia at (34.981534, -84.370293). It is bordered to the north by its twin city of Copperhill, Tennessee. The two are situated as a single town along a river, known as the Toccoa River in Georgia and the Ocoee River in Tennessee. The change takes place in the middle of town at the state line, which runs diagonally relative to the street grid, which is aligned with the river rather than the border. The boundary also means that the McCaysville side is in area code 706, while the Copperhill side is in area code 423.