Statistics for occurrence #1 of “Headquarters” in chapter 26, page 455 of Alfred Roman, The military operations of General Beauregard in the war between the states, 1861 to 1865:

...ort Pulaski to-day: four steamers, one river steamboat, one large sailing ship, one schooner under way, outward-bound, and ten or fifteen schooners at anchor. W. S. Walker, Brig.-Genl. Headquarters , Department S. C. And Ga., Charleston, S. C., Nov. 3d, 1862. Capt. D. N. Ingraham, C. S. N., Comdg. C. S. naval forces, Charleston, S. C. Captain,—You will greatly oblige me by furnishing, ...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Headquarters (Washington, United States) 1,024 466 0 0 0 user votes
Headquarters (New Jersey, United States) 132 124 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.