The Washington Post has a neat interactive map of Civil War battles. One can set the date of battles displayed. The results show what battles were fought there and casualties are given in a range of circle sizes. Sadly, but reasonably understandable, most battles do not have any additional information. However, the major battles are labeled and clicking the battle circle will give the user more information on the background of the engagement. Finally, since the map is powered by Google Maps, one can zoom in and see things like the battles of 1862 around Richmond.
Press the play button below to watch the war unfold over time. Drag the scrubber or click on the months and years to change the date range. Roll over the circles for more information on each battle.