Statistics for occurrence #1 of “Colorado” in chapter 2.7 of The Photographic History of The Civil War: in ten volumes, Thousands of Scenes Photographed 1861-65, with Text by many Special Authorities, Volume 1: The Opening Battles.:

...ssee, 298; Kentucky, 138; Ohio, 3; Indiana, 4; Illinois, 1; Missouri, 244; Minnesota, 6; California, 6; Kansas, 7; Oregon, 4; Nevada, 2; Washington Territory, 1; Utah, 1; New Mexico, 19; Nebraska, 2; Colorado , 4; Indian Territory, 17; Dakota, 11; Arizona, 4; and Idaho, 1. It soon became evident that the official record of the War of 1861-5 must be compiled for the purposes of Government administration...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Colorado (Colorado, United States) 1,628 4 0 0 0 user votes
Colorado (Texas, United States) 24 0 0 0 0 user votes
Colorado 2 0 0 0 0 user votes
Colorado (Alaska, United States) 0 0 0 0 0 user votes
Colorado (Costa Rica) 0 0 0 0 0 user votes
Colorado (Honduras) 0 0 0 0 0 user votes
Colorado (Mexico, Mexico) 0 0 0 0 0 user votes
Colorado (New Mexico, United States) 0 0 0 0 0 user votes
Colorado (Rondonia, Brazil) 0 0 0 0 0 user votes
Colorado (Texas, United States) 0 0 0 0 0 user votes
Colorado (Utah, 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.