Statistics for occurrence #1 of “Mexico” in chapter 5, page 123 of G. S. Hillard, Life and Campaigns of George B. McClellan, Major-General , U. S. Army:

...that happy element in our lot — had an-influence in the same direction. We had read of armies, but practically we knew nothing about them. The battles of the War of 1812 and of the war with Mexico had been fought with small and manageable bodies of men; but so immense an army as that which was encamped in and around Washington
...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
† Mexico (Mexico, Mexico) 8,518 42 0 0 0 user votes
Mexico (Mexico) 1,918 16 0 0 0 user votes
Mexico (New York, United States) 45 0 1 0 0 user votes
Mexico (Indiana, United States) 8 0 0 0 0 user votes
Mexico (Kentucky, United States) 0 0 0 0 0 user votes
Mexico (Maine, United States) 0 0 0 0 0 user votes
Mexico (Maryland, United States) 0 0 0 0 0 user votes
Mexico (Ohio, United States) 0 0 0 0 0 user votes
Mexico (Ohio, United States) 0 0 0 0 0 user votes
Mexico (Pennsylvania, United States) 0 0 0 0 0 user votes
Mexico (Pennsylvania, United States) 0 0 0 0 0 user votes
Mexico (South Carolina, 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.