Statistics for occurrence #1 of “Portsmouth” in chapter 1, page 540 of Cambridge History of American Literature: volume 3:

...
, which appeared in that year at Pittsburg, Portsmouth , Middletown, New Haven, Norwich, and Boston, and which went through several mythadding editions in the next few years. Its vogue is noted here merely to emphasize the fact that the American public ...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Portsmouth (New Hampshire, United States) 470 1 134 1 0 user votes
Portsmouth (United Kingdom) 107 0 13 0 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.