Statistics for occurrence #1 of “Headquarters” in chapter 197 of Rebellion Record: a Diary of American Events: Documents and Narratives, Volume 2.:

...
Headquarters Western Department, St. Louis, August 13, 1861. Col. E. D. Townsend:-- Gen. Lyon, in three columns, under himself, Siegel, and Sturgis, attacked the enemy at half-past 6 o'clock on the morning of...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Headquarters (Washington, United States) 1,024 64 0 0 0 user votes
Headquarters (New Jersey, United States) 132 0 0 0 0 user votes
Headquarters (Kentucky, United States) 84 0 0 0 0 user votes
Headquarters (Arizona, United States) 2 0 0 0 0 user votes
Headquarters (Idaho, 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.