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