Here is the full list of all 39 Ultimate General: Civil War achievements.
Win the historical battle of Gaines' Mill as Union
Win the historical battle of Shiloh as Union
7th Level Confederate Medal (can be achieved only on "Major General" difficulty)
6th Level Confederate Medal (can be achieved only on "Major General" difficulty)
5th Level Confederate Medal (can be achieved only on "Brigadier General" difficulty or higher)
4th Level Confederate Medal
3rd Level Confederate Medal
2nd Level Confederate Medal
1st Level Confederate Medal
Win a campaign battle
Win the historical battle of Cold Harbor as Confederate
Win the historical battle of Chickamauga as Confederate
Win the historical battle of Gettysburg as Confederate
Win the historical battle of Chancellorsville as Confederate
Win the historical battle of Stones River as Confederate
Win the historical battle of Fredericksburg as Confederate
Win the historical battle of Antietam as Confederate
Win the historical battle of 2nd Manassas as Confederate
Win the historical battle of Malvern Hill as Confederate
Win the historical battle of Gaines' Mill as Confederate
Win the historical battle of Shiloh as Confederate
Win the historical battle of Bull Run as Union
Win the historical battle of Bull Run as Confederate
7th Level Union Medal (can be achieved only on "Major General" difficulty)
6th Level Union Medal (can be achieved only on "Major General" difficulty)
5th Level Union Medal (can be achieved only on "Brigadier General" difficulty or higher)
4th Level Union Medal
3rd Level Union Medal
2nd Level Union Medal
1st Level Union Medal
Win the historical battle of Antietam as Union
Win the historical battle of Chancellorsville as Union
Win the historical battle of Chickamauga as Union
Win the historical battle of Cold Harbor as Union
Win the historical battle of Fredericksburg as Union
Win the historical battle of Gettysburg as Union
Win the historical battle of Malvern Hill as Union
Win the historical battle of 2nd Manassas as Union
Win the historical battle of Stones River as Union