Charge! is about Civil War combat, refighting various Civil War battles as the Union or Confederates on an operational level.
This is a turn-based game of low to moderate complexity, with size, skill, and morale of the units being the key determiners of victory.
This is the Windows version of the DOS classic, "Civil War Battle Set", which can probably still be found on the internet today (try searching "hutsell").
That game, while primitive by today's standards, was a tremendous amount of fun to play. The graphics and user interface have been improved, but the fun is still there.