This work (The Field of Battle and Prominent Union Generals, Creator: Ensign & Bridgman, New York; Producer: The British Library), identified by The British Library, is free of known copyright restrictions.

I promised some more maps from the U.S. Civil War project, so here's another one, The Field of Battle and Prominent Union Generals [1864?].  And Mr Sherman, it's time for your close-up:

[M.J.S.]