Statistics for occurrence #1 of “Gettysburg” in entry adams-charles-francis-2nd of Harper's Encyclopedia of United States History:

...in mind, will it be well for us, will it be well for our country, will it be well for those whose name we bear, that our bones also do not moulder with those of our brave comrades beneath the sods of Gettysburg , or that our graves do not look down on the swift-flowing Mississippi from the historic heights of Vicksburg.
...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Gettysburg (Pennsylvania, United States) 7,452 224 1,368 10 0 user votes
Gettysburg (South Carolina, United States) 0 0 0 0 0 user votes
Gettysburg (South Dakota, 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.