Statistics for occurrence #1 of “Union Mills” in chapter 14 of The Photographic History of The Civil War: in ten volumes, Thousands of Scenes Photographed 1861-65, with Text by many Special Authorities, Volume 5: Forts and Artillery.:

... Union Mills
O. E. Hunt, Captain, United States Army With miles of black and yellow mud between them and the base of ...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Union Mills (Maryland, United States) 28 0 0 0 0 user votes
Union Mills (Virginia, United States) 2 0 2 0 0 user votes
Union Mills (Indiana, United States) 0 0 0 0 0 user votes
Union Mills (Iowa, United States) 0 0 0 0 0 user votes
Union Mills (Kentucky, United States) 0 0 0 0 0 user votes
Union Mills (New Jersey, United States) 0 0 0 0 0 user votes
Union Mills (New York, United States) 0 0 0 0 0 user votes
Union Mills (North Carolina, United States) 0 0 0 0 0 user votes
Union Mills (Oregon, United States) 0 0 0 0 0 user votes
Union Mills (Pennsylvania, United States) 0 0 0 0 0 user votes
Union Mills (West Virginia, 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.