Statistics for occurrence #1 of “Hagerstown” in chapter 7.16 of Robert Underwood Johnson, Clarence Clough Buell, Battles and Leaders of the Civil War: The Opening Battles. Volume 1.:

... or local feeling than to general military considerations. The prompt advance of the Union forces under McClellan to West Virginia was to protect that new-born free State. Patterson's movement to Hagerstown and thence to Harper's Ferry was to prevent Maryland from joining or aiding the rebellion, to re-open the Baltimore and Ohio railroad, and prevent invasion from the Shenandoah Valley. The Southerne...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Hagerstown (Maryland, United States) 2,520 2 172 0 0 user votes
Hagerstown (Indiana, United States) 6 0 2 0 0 user votes
Hagerstown (New Jersey, United States) 4 0 0 0 0 user votes
Hagerstown (Ohio, United States) 4 0 2 0 0 user votes
Hagerstown (Ohio, United States) 0 0 0 0 0 user votes
Hagerstown (Ohio, United States) 0 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.