Fourth Brigade - Second Division - Army of the Ohio
Brigadier General Lovell H. Rousseau

This brigade formed in line of battle on Crittenden's right at 8 a.m., April 7, 1862, in front of the camp of the third Iowa, in the following order: Sixth Indiana on the left, First Ohio in the center, First Battalions of Nineteenth, Fifteenth, and Sixteenth United Stated Infantry on the right, and the Fifth Kentucky in reserve. The Fifteenth Michigan was attached temporarily to this brigade and served with it all day. At 9 a.m. the brigade advanced across Tilghman Creek and engaged Trabue's brigade until about 11 a.m., when Trabue retired and Rousseau advanced to Woolf Field, where he found a force of the enemy on its west side. His ammunition being exhausted, Rousseau retired and Kirk's brigade took his place in the first line. As soon as ammunition was supplied Rousseau took position again in the front line and engaged until he retired from the field.

6th Indiana - Colonel Thomas T. Crittenden

5th Kentucky - Colonel Harvey M. Buckley

1st Ohio - Colonel Benjamin F. Smith

United States Infantry - Major John H. King

1st Battalion, 15th United States Infantry - Captain Peter T. Swain

1st Battalion, 16th United States Infantry - Captain Edward F. Townsend

1st Battalion, 19th United States Infantry - Captain Stephen D. Carpenter