Statistics for occurrence #1 of “Callao” in chapter 31 of Thomas Wentworth Higginson, Harvard Memorial Biographies:

...more of the world, which he would not probably do if he made the return voyage, led him to leave the Peabody; and within a few days he shipped again, in the Commonwealth, an American vessel bound for Callao . He carried out with him from Boston several Latin and Greek text-books, and other books for reading and study, intending to use them in his spare hours, so as to reenter College on his return with...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Callao (Peru) 90 6 4 0 0 user votes
Callao (Missouri, United States) 1 0 1 0 0 user votes
Callao (Peru) 0 0 0 0 0 user votes
Callao (Utah, United States) 0 0 0 0 0 user votes
Callao (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.