Berthold Fernow (28 November 1837 – 3 March 1908) was a German-born American (New York State) historian, author and librarian.

Berthold Fernow was born in Inowrocław (now part of Poland), Province of Posen, Prussia on 28 November 1837.

He was educated at the royal gymnasium of Our Lady at Magdeburg, Saxony, and at a similar institution at Bromberg, Posen, in 1858.

[1] He then emigrated to the United States, served during the American Civil War as lieutenant of the 3rd U. S. colored troops, and subsequently as topographical engineer.

[1] For a time, he was one of the state librarians, keeper of the historical records at Albany, New York, and the editor of the 12th, 13th, and 14th volumes of Documents Relating to the Colonial History of New York (Albany, 1877–85), State Archives (vol.