The Civil War was one of the deadliest conflicts in United States history, with over 10,000 battles between 1861 and 1865. From Vermont to as far away as Arizona, Union and Confederate soldiers would repeatedly clash after the First Battle of Bull Run on July 21, 1861. For the next four years, this conflict would lead to the deaths of more than 360,000 Union and 258,000 Confederate deaths. With this in mind, let’s look at the 20 deadliest battles of the Civil War.
20. Battle of Franklin
![Battle of Franklin](https://history-computer.com/wp-content/uploads/2024/06/Franklin-Nashville_campaign.svg_-1200x893.jpg)
- Dates: November 30, 1864
- Union Forces: 27,000
- Confederate Forces: 27,000
- Casualties: 8,578 (2,326 Union; 6,252 Confederate)
- Winner: Union victory
19. Battle of Cedar Creek
![](https://history-computer.com/wp-content/uploads/2024/06/7993979688_f1d3860297_b.jpg)
- Dates: October 19, 1864
- Union Forces: 31,610
- Confederate Forces: 21,102
- Casualties: 8,674 (5,764 Union; 2,910 Confederate)
- Winner: Union victory
18. Battle of Opequon
![](https://history-computer.com/wp-content/uploads/2024/06/10091621565_d9d00e7e88_b.jpg)
- Dates: September 19, 1864
- Union Forces: 40,000
- Confederate Forces: 15,514
- Casualties: 9,035 (5,020 Union; 4,015 Confederate)
- Winner: Union victory
17. Battle of Nashville
![](https://history-computer.com/wp-content/uploads/2024/06/Original_Battle_of_Nashville_Monument.jpg)
- Dates: December 15-16, 1864
- Union Forces: 55,000
- Confederate Forces: 30,000
- Casualties: 9,061 (3,061 Union; 6,000 Confederate)
- Winner: Union victory
16. Battle of Seven Pines
![Battle of Fair Oaks](https://history-computer.com/wp-content/uploads/2024/06/Battle_of_Fair_Oaks_Franklins_corps_retreating-1200x814.jpg)
- Dates: May 31-June 1, 1862
- Union Forces: 34,000
- Confederate Forces: 39,000
- Casualties: 11,165 (5,031 Union; 6,134 Confederate)
- Winner: Both sides claimed victory
15. Battle of Atlanta
![Battle of Atlanta](https://history-computer.com/wp-content/uploads/2024/06/1280px-Battle_two_miles_west_of_Atlanta_July_29th_1864-1200x713.jpg)
- Dates: July 22nd, 1864
- Union Forces: 34,863
- Confederate Forces: 40,438
- Casualties: 12,140 (3,641 Union; 8,499 Confederate)
- Winner: Union victory
14. Battle of Missionary Ridge
![](https://history-computer.com/wp-content/uploads/2024/06/10484057403_c6d2f651fd_b.jpg)
- Dates: November 25, 1863
- Union Forces: 56,359
- Confederate Forces: 44,010
- Casualties: 12,491 (5,824 Union; 6,667 Confederate)
- Winner: Union victory
13. Battle of Gaines’s Mill
![Battle of Gaines's Mill](https://history-computer.com/wp-content/uploads/2024/06/Gaines_Mill_Jacksons_marker-1200x902.jpg)
- Dates: June 27, 1862
- Union Forces: 34,214
- Confederate Forces: 57,018
- Casualties: 14,830 (6,837 Union; 7,993 Confederate)
- Winner: Confederate victory
12. Battle of 2nd Petersburg
![](https://history-computer.com/wp-content/uploads/2024/06/GettyImages-1068421904-1.jpg)
- Dates: June 15-18, 1864
- Union Forces: 62,000
- Confederate Forces: 38,000
- Casualties: 15,385 (11,386 Union; 4,000 Confederate)
- Winner: Union victory
11. Battle of Cold Harbor
![](https://history-computer.com/wp-content/uploads/2024/06/NPS_Battle_of_Cold_Harbor_marker_1-scaled.jpg)
- Dates: May 31-June 12, 1864
- Union Forces: 108,000
- Confederate Forces: 59,000
- Casualties: 17,332 (12,737 Union; 4,595 Confederate)
- Winner: Confederate victory
10. Battle of Fredericksburg
![](https://history-computer.com/wp-content/uploads/2024/06/2748752316_0bf726c8af_b.jpg)
- Dates: December 11-15, 1862
- Union Forces: 114,000
- Confederate Forces: 72,500
- Casualties: 18,030 (12,653 Union; 5,377 Confederate)
- Winner: Confederate victory
9. Battle of 2nd Bull Run
![](https://history-computer.com/wp-content/uploads/2024/06/Brooklyn_14th_2nd_Battle_of_Manassas_Twilight_Clash_Sign-scaled.jpg)
- Dates: August 29-30, 1862
- Union Forces: 62,000
- Confederate Forces: 50,000
- Casualties: 18,300 (10,000 Union; 8,300 Confederate)
- Winner: Confederate victory
8. Battle of Antietam
![](https://history-computer.com/wp-content/uploads/2024/06/cHJpdmF0ZS9sci9pbWFnZXMvd2Vic2l0ZS8yMDI0LTAyL2xyL2dldHR5MTA5OWNmLWltYWdlLmpwZw.webp)
- Dates: September 17, 1862
- Union Forces: 75,500
- Confederate Forces: 38,000
- Casualties: 22,717 (12,401 Union; 10,316 Confederate)
- Winner: Union victory
7. Battle of Shiloh
![](https://history-computer.com/wp-content/uploads/2024/06/General_Ulysses_S._Grant_and_the_Battle_of_Shiloh-1200x695.jpg)
- Dates: April 6-7, 1862
- Union Forces: 66,812
- Confederate Forces: 44,699
- Casualties: 23,746 (13,047 Union; 10,699 Confederate)
- Winner: Union victory
6. Battle of Stones River
![](https://history-computer.com/wp-content/uploads/2024/06/cHJpdmF0ZS9sci9pbWFnZXMvd2Vic2l0ZS8yMDIyLTA5L2xvYzIwMjE3NTY0NjktaW1hZ2UuanBn.webp)
- Dates: December 31, 1862 – January 2, 1863
- Union Forces: 41,400
- Confederate Forces: 35,000
- Casualties: 24,645 (12,906 Union; 11,739 Confederate)
- Winner: Union victory
5. Battle of The Wilderness
![](https://history-computer.com/wp-content/uploads/2024/06/2747998571_3994bbfc95_b.jpg)
- Dates: May 5-7, 1864
- Union Forces: 101,895
- Confederate Forces: 61,025
- Casualties: 28,699 (17,666 Union; 11,033 Confederate)
- Winner: Inconclusive
4. Battle of Chancellorsville
![](https://history-computer.com/wp-content/uploads/2024/06/2747952817_892015070a_b.jpg)
- Dates: May 1-4, 1864
- Union Forces: 133,868
- Confederate Forces: 60,298
- Casualties: 30,500 (17,197 Union, 13,303 Confederate)
- Winner: Confederate victory
3. Battle of Spotsylvania Court House
![](https://history-computer.com/wp-content/uploads/2024/06/2748895430_94903f4884_b.jpg)
- Dates: May 8-21, 1864
- Union Forces: 100,000
- Confederate Forces: 52,000
- Casualties: ~31,086 (18,399 Union, 12,687 Confederate)
- Winner: Inconclusive
2. Battle of Chickamauga
![](https://history-computer.com/wp-content/uploads/2024/06/Monument_to_Kentucky_Units_at_the_Battle_of_Chickamauga_image_2-scaled.jpg)
- Dates: September 19-20, 1863
- Union Forces: 60,000
- Confederate Forces: 65,000
- Casualties: 34,624 (16,173 Union; 18,451 Confederate)
- Winner: Confederate victory
1. Battle of Gettysburg
![](https://history-computer.com/wp-content/uploads/2024/05/shutterstock-315000416-huge-licensed-scaled.jpg)
- Dates: July 1-3, 1863
- Union Forces: 93,321
- Confederate Forces: 76,699
- Casualties: ~51,000 (23,049 Union; 28,063 Confederate)
- Winner: Union victory
The image featured at the top of this post is ©Zack Frank/Shutterstock.com.