Statistics for occurrence #1 of “St. John's river” in chapter 9 of Southern Historical Society Papers, Volume 4.:

...sland on the coast of South Carolina, with Charleston harbor blockaded and the city of Charleston besieged — of Fort Pulaski, at the mouth of the Savannah river, in Georgia--of the mouth of the St. John's river , Key West and Pensacola, in Florida--of the lower Mississippi, New Orleans, Baton Rouge, and Memphis, with Vicksburg and Port Hudson besieged, the fall of which latter towns was all that was necessar...
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St. John's River (Missouri, United States) 5 0 3 0 0 user votes

† This entity has been selected by the automated classifier as the most likely match in this context. It may or may not be the correct match.