Some examples, some very big battles
January 19, 1862: Battle of Mill Springs
Casualties: 671
232 Union
439 Confederate
February 6, 1862: Battle of Fort Henry
Casualties: 119
40 Union
79 Confederate
February 11, 1862: Battle of Fort Donelson
Casualties: 17,398
2,331 Union
15,067 Confederate
December 13, 1862: Battle of Fredericksburg
Casualties: 17,929
13,353 Union
4,576 Confederate
December 31, 1862 – January 2, 1863: Battle of Stones River
Casualties: 23,515
13,249 Union
10,266 Confederate
January 9-11, 1863: Battle of Arkansas Post
Casualties: 6,547
1,047 Union
5,500 Confederate
November – December, 1864: Sherman's March to the Sea
Casualties: Unknown
November 29, 1864: Battle of Spring Hill
Casualties: Unknown
November 30, 1864: Battle of Franklin
Casualties: 8,587
2,326 Union
6,261 Confederate
December 15-16, 1864: Battle of Nashville
Casualties: 6,602
2,140 Union
4,462 Confederate
January 13-15, 1865: Second Battle of Fort Fisher
Casualties: 2,000
Battle of Pea Ridge
Mar 7, 1862 – Mar 8, 1862