11th Illinois

On back of monument:
11th Infantry,
Commanded by
1. Lieut. Col. T. E. G. Ransom, Wounded.
2. Major Garrett Nevins, Wounded.
3. Capt. L. D. Waddell.
Went into battle on this line with 9 companies (one company on picket) about 9.00 a.m., April 6, 1862, receiving a fire that killed or wounded, in a few minutes, the Lieut. Colonel, Major, four line officers and many men. This position was held about two hours when they fell back 500 yards. The regiment lost in the battle 1 officer and 16 men killed; 4 officers and 65 men wounded; 17 men missing; total, 103.

Note:

I would have included a picture of the headquarters monument for Marsh but none exists. You can read his official report here. Interestingly he signed it "March" but it appears on monuments as "Marsh."

20th Illinois

On back of monument:
20th Infantry,
Commanded by
1. Lieut. Col. E. Richards, Wounded.
2. Major F. A. Bartleson, Wounded.
3. Capt. O. Frisbie.
Went into position here about 9.00 a.m., April 6, 1862, and held it until 11 a.m., when it withdrew, going to the rear of its own camp where it formed a new line. The regiment lost in the battle 1 officer and 21 men killed; 5 officers and 102 men wounded; 7 men missing; total, 136.

45th Illinois

On back of monument:
45th Infantry,
Commanded by Col. John E. Smith.
Went into battle on this line about 9.00 a.m., April 6, 1862, and maintained this position until 11.00 a.m., when it joined the division on a new line. The regiment lost 1 officer and 22 men killed; 17 officers and 170 men wounded; 3 men missing; total, 213.

48th Illinois

On back of monument:
48th Infantry,
Commanded by
1. Col. I. N. Haynie, Wounded.
2. Lieut. Col. W. W. Sanford, Wounded.
3. Major M. Mayfield.
Went into line of battle here about 9.00 a.m., April 6, 1862, and held it until 10.50 a.m., when it was driven back 500 yards. The regiment lost in the battle 1 officer and 17 men killed; 4 officers and 108 men wounded; 1 officer and 2 men missing; total, 133.