Statistics for occurrence #1 of “Potomac River” in chapter 16 of The Photographic History of The Civil War: in ten volumes, Thousands of Scenes Photographed 1861-65, with Text by many Special Authorities, Index:

...f, X., 290. Potato-digging by Grant's men, VIII, 198-199. L, 350. Potomac, The Army of the (see also Army of the Potomac), I., 282. bridge over, V., 272; VII., 41. Potomac River : I., 62; in Virginia, II., 19, 56; in Maryland and Virginia, II., 229; view of, from Berlin Heights, II., 266; Meade's army crossing at Berlin, II., 267; V., 80, 258; VI., 39, 92; flotilla and batter...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Potomac River (United States) 286 0 0 0 0 user votes
Potomac River (Maryland, United States) 2 0 0 0 0 user votes
Potomac River (Maryland, United States) 2 0 0 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.