Statistics for occurrence #1 of “Washington” in chapter 4, page 43 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.:

...siege of Savannah, December 10 to 21, 1864, and served throughout the campaign of the Carolinas, January to April, 1865. After being present at the surrender of Johnston and his army, it marched to Washington via Richmond, and took part in the grand review. It was mustered out on June 14, 1865.
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Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Washington (United States) 21,192 172 3,586 0 0 user votes
Washington (Washington, United States) 232 0 0 0 0 user votes
Washington (Virginia, United States) 224 0 4 0 0 user votes
Washington (Alabama, United States) 88 0 0 0 0 user votes
Washington (West Virginia, United States) 14 0 2 0 0 user votes
Washington (Georgia, United States) 6 0 6 0 0 user votes
Washington (Idaho, United States) 4 0 4 0 0 user votes
Washington (California, United States) 2 2 0 0 0 user votes
Washington (Missouri, United States) 2 0 2 0 0 user votes
Washington (Louisiana, United States) 1 0 1 0 0 user votes
Washington (Arkansas, United States) 0 0 0 0 0 user votes
Washington (Kansas, United States) 0 0 0 0 0 user votes
Washington (Maine, United States) 0 0 0 0 0 user votes
Washington (Michigan, United States) 0 0 0 0 0 user votes
Washington (Minnesota, United States) 0 0 0 0 0 user votes
Washington (Mississippi, United States) 0 0 0 0 0 user votes
Washington (Missouri, United States) 0 0 0 0 0 user votes
Washington (Nebraska, United States) 0 0 0 0 0 user votes
Washington (Nevada, United States) 0 0 0 0 0 user votes
Washington (New Jersey, United States) 0 0 0 0 0 user votes
Washington (New Mexico, United States) 0 0 0 0 0 user votes
Washington (New Mexico, United States) 0 0 0 0 0 user votes
Washington (Ohio, United States) 0 0 0 0 0 user votes
Washington (Ohio, United States) 0 0 0 0 0 user votes
Washington (Ohio, United States) 0 0 0 0 0 user votes
Washington (Oklahoma, United States) 0 0 0 0 0 user votes
Washington (Texas, United States) 0 0 0 0 0 user votes
Washington (United Kingdom) 0 0 0 0 0 user votes
Washington (Utah, United States) 0 0 0 0 0 user votes
Washington (Vermont, 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.