In the case of State of Georgia v. State of South Carolina in 1921, the Supreme Court was tasked with settling a boundary dispute between the two states. The disagreement centered around several islands located on Savannah River and whether they fell within Georgia's or South Carolina's jurisdiction. The court ruled that all islands lying to the northward and eastward of main channel belong to South Carolina, while those lying southward and westward belong to Georgia. This decision was based on historical treaties, charters, usage over time as well as physical features such as channels and watercourses which were used for demarcation purposes.

In the dissenting opinion for the case between Georgia and South Carolina, it was argued that the majority's decision to grant South Carolina sovereignty over certain disputed islands in Savannah River was incorrect. The dissenters believed that historical evidence clearly showed these islands were part of Georgia when both states joined the Union. They also disagreed with how much weight was given to a 1787 agreement between commissioners from both states, arguing this document did not definitively resolve their boundaries. Furthermore, they felt there wasn't enough consideration given to subsequent actions by both states which indicated mutual recognition of Georgia's jurisdiction over these areas. Lastly, they raised concerns about potential implications on other boundary disputes if such an ambiguous agreement could be used as definitive proof of state lines.