< to June • July 1861

Commanded by Brigadier General George Cadwallader

The 1st Division was discontinued on July 25, 1861.

1st Brigade Colonel George Thomas
6th Pennsylvania Infantry Regiment Colonel James Nagle  7/18 to Harrisburg to muster out
21st Pennsylvania Infantry Regiment Colonel John F. Ballier  7/31 to Philadelphia to muster out
23rd Pennsylvania Infantry Regiment Colonel Charles P. Dare  7/20 to Philadelphia to muster out
Philadelphia City Troop Cavalry Captain Thomas James
2nd United States Cavalry (Cos. ACF&K)  to Dep. Shenandoah – 1st Brig.
4th U.S. Artillery (detatchment) Captain Abner Doubleday 1 8″ howitzer and 1 24-pounder
3rd Brigade Brig. Gen. Alpheus S. Williams
7th Pennsylvania Infantry Regiment Colonel William I. Irwin to Harrisburg 7/22 for muster out
8th Pennsylvania Infantry Regiment Colonel A.H. Emley to Harrisburg 7/22 for muster out
10th Pennsylvania Infantry Regiment Colonel Sullivan A. Meredith to Harrisburg 7/23 for muster out
20th Pennsylvania Infantry Regiment Colonel Wiliam H. Gray to Philadelphia 7/24 for muster out
4th Brigade Col. J. C. Longenecker (until 7/2)
Colonel Dixon S. Miles
9th Pennsylvania Infantry Regiment Colonel Henry C. Longnecker 7/21 to Harrisburg to muster out
13th Pennsylvania Infantry Regiment Colonel Thomas A. Rowley 7/21 to Harrisburg to muster out
16th Pennsylvania Infantry Regiment Colonel Thomas A. Ziegle 7/21 to Harrisburg to muster out