Statistics for occurrence #1 of “Portsmouth” in entry winslow-john-ancrum of Harper's Encyclopedia of United States History:

...f Cherbourg, France. For this action he was promoted commodore. He was in command of the Gulf Squadron in 1866-67, of the Pacific fleet in 1871, and, at the time of his death, of the navy-yard at Portsmouth . He died in Boston, Sept. 29, 1873.
...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
† Portsmouth (New Hampshire, United States) 470 225 134 39 0 user votes
Portsmouth (United Kingdom) 107 15 13 5 0 user votes
Portsmouth (Dominica) 0 0 0 0 0 user votes
Portsmouth (Iowa, United States) 0 0 0 0 0 user votes
Portsmouth (Kentucky, United States) 0 0 0 0 0 user votes
Portsmouth (Virginia, 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.