The following is a list of the units of the United States Regular Army during the American Civil War.
Infantry
- 1st Infantry Regiment
- 2nd Infantry Regiment
- 3rd Infantry Regiment
- 4th Infantry Regiment
- 5th Infantry Regiment
- 6th Infantry Regiment
- 7th Infantry Regiment
- 8th Infantry Regiment
- 9th Infantry Regiment
- 10th Infantry Regiment
- 11th Infantry Regiment
- 12th Infantry Regiment
- 13th Infantry Regiment
- 14th Infantry Regiment
- 15th Infantry Regiment
- 16th Infantry Regiment
- 17th Infantry Regiment
- 18th Infantry Regiment
- 19th Infantry Regiment
Cavalry
- 1st Cavalry Regiment
- 2nd Cavalry Regiment
- 3rd Cavalry Regiment
- 4th Cavalry Regiment
- 5th Cavalry Regiment
- 6th Cavalry Regiment
Artillery
- 1st Artillery Regiment
- 2d Artillery Regiment
- 3d Artillery Regiment
- 4th Artillery Regiment
- 5th Artillery Regiment