Statistics for occurrence #1 of “Harper's Ferry” in chapter 9, page 920 of Comte de Paris, History of the Civil War in America. Vol. 3.:

...
the Potomac at Berlin; the Twelfth corps, from Pleasant Valley to near Hillsboroa, crossing the Potomac and Shenandoah rivers at Harper's Ferry . Buford's cavalry division moved from Purcellville, via Philomont, to near Rector's Cross-roads. McIntosh's brigade, of Gregg's cavalry division, moved from Harper's Ferry toward Purcellville, an...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Harper's Ferry (West Virginia, United States) 10,974 144 304 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.