March 1862 • to April >

Commanded by Brigadier General Erasmus D. Keyes

The 4th Corps was created on March 3, 1862 and announced March 13, 1862.

First Division	Brigadier General Darius N. Couch
1st Brigade	Colonel H. S. Briggs
2nd Brigade	Brigadier General L. P. Graham
3rd Brigade	Brigadier General J. J. Peck
Second Division	Brigadier General William F. Smith
1st Brigade	Brigadier General Winfield S. Hancock
2nd Brigade	Brigadier General W. T. H. Brooks
3rd Brigade	Brigadier General J. W. Davidson
Third Division	Brigadier General Silas Casey
1st Brigade	Brigadier General H. M. Naglee
2nd Brigade	Brigadier General William H. Keim
3rd Brigade	Brigadier General I. N. Palmer
Cavalry
8th Pennsylvania Cavalry Regiment	Colonel David McM. Gregg	from Porter’s Division