Statistics for occurrence #1 of “Mount Vernon” in chapter 9, page 164 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.:

...he chief localities that were thus utilized were Richmond, Virginia; Fayetteville, North Carolina; Charleston, South Carolina; Augusta, Savannah, and Macon, Georgia; Nashville and Memphis, Tennessee; Mount Vernon
...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Mount Vernon (Virginia, United States) 322 2 8 0 0 user votes
Mount Vernon (Missouri, United States) 63 0 5 0 0 user votes
Mount Vernon (Kentucky, United States) 57 0 5 0 0 user votes
Mount Vernon (Arkansas, United States) 15 0 3 0 0 user votes
Mount Vernon (Arkansas, United States) 2 0 0 0 0 user votes
Mount Vernon (Ohio, United States) 2 0 0 0 0 user votes
Mount Vernon (Georgia, United States) 1 0 1 0 0 user votes
Mount Vernon (Michigan, United States) 1 0 1 0 0 user votes
Mount Vernon (New York, United States) 1 0 1 0 0 user votes
Mount Vernon (Alabama, United States) 0 0 0 0 0 user votes
Mount Vernon (Alabama, United States) 0 0 0 0 0 user votes
Mount Vernon (Alabama, United States) 0 0 0 0 0 user votes
Mount Vernon (Arizona, United States) 0 0 0 0 0 user votes
Mount Vernon (Arkansas, United States) 0 0 0 0 0 user votes
Mount Vernon (California, United States) 0 0 0 0 0 user votes
Mount Vernon (Georgia, United States) 0 0 0 0 0 user votes
Mount Vernon (Indiana, United States) 0 0 0 0 0 user votes
Mount Vernon (Iowa, United States) 0 0 0 0 0 user votes
Mount Vernon (Kansas, United States) 0 0 0 0 0 user votes
Mount Vernon (Maine, United States) 0 0 0 0 0 user votes
Mount Vernon (Maryland, United States) 0 0 0 0 0 user votes
Mount Vernon (Mississippi, United States) 0 0 0 0 0 user votes
Mount Vernon (Mississippi, United States) 0 0 0 0 0 user votes
Mount Vernon (Missouri, United States) 0 0 0 0 0 user votes
Mount Vernon (Missouri, United States) 0 0 0 0 0 user votes
Mount Vernon (Missouri, United States) 0 0 0 0 0 user votes
Mount Vernon (Montana, United States) 0 0 0 0 0 user votes
Mount Vernon (Nebraska, United States) 0 0 0 0 0 user votes
Mount Vernon (Nebraska, United States) 0 0 0 0 0 user votes
Mount Vernon (New Jersey, United States) 0 0 0 0 0 user votes
Mount Vernon (New Mexico, United States) 0 0 0 0 0 user votes
Mount Vernon (New York, United States) 0 0 0 0 0 user votes
Mount Vernon (New York, United States) 0 0 0 0 0 user votes
Mount Vernon (North Carolina, United States) 0 0 0 0 0 user votes
Mount Vernon (North Carolina, United States) 0 0 0 0 0 user votes
Mount Vernon (North Carolina, United States) 0 0 0 0 0 user votes
Mount Vernon (Oregon, United States) 0 0 0 0 0 user votes
Mount Vernon (Oregon, United States) 0 0 0 0 0 user votes
Mount Vernon (Pennsylvania, United States) 0 0 0 0 0 user votes
Mount Vernon (Pennsylvania, United States) 0 0 0 0 0 user votes
Mount Vernon (Pennsylvania, United States) 0 0 0 0 0 user votes
Mount Vernon (South Carolina, United States) 0 0 0 0 0 user votes
Mount Vernon (South Dakota, United States) 0 0 0 0 0 user votes
Mount Vernon (Tennessee, United States) 0 0 0 0 0 user votes
Mount Vernon (Tennessee, United States) 0 0 0 0 0 user votes
Mount Vernon (Tennessee, United States) 0 0 0 0 0 user votes
Mount Vernon (Tennessee, United States) 0 0 0 0 0 user votes
Mount Vernon (Tennessee, United States) 0 0 0 0 0 user votes
Mount Vernon (Tennessee, United States) 0 0 0 0 0 user votes
Mount Vernon (Tennessee, United States) 0 0 0 0 0 user votes
Mount Vernon (Tennessee, United States) 0 0 0 0 0 user votes
Mount Vernon (Texas, United States) 0 0 0 0 0 user votes
Mount Vernon (Virginia, United States) 0 0 0 0 0 user votes
Mount Vernon (Washington, United States) 0 0 0 0 0 user votes
Mount Vernon (West Virginia, United States) 0 0 0 0 0 user votes
Mount Vernon (Western Australia, Australia) 0 0 0 0 0 user votes
Mount Vernon (Wisconsin, 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.