General Staff.
- Lieutenant-Colonel Ethan Allen Hitchcock, Assistant Inspector General.
- Captain Henry Lee Scott, Acting Adjutant General.
- First-Lieutenant T. Williams, Aid-de-camp.
- Brevet First-Lieutenant George William Lay, Aid-de-camp.
- Second-Lieutenant Schuyler Hamilton, Aid-de-camp.
- Major J.P. Gaines, Volunteer Aid-de-camp.
Engineer Corps.
Major John Lind Smith, Chief; Captain Robert Edward Lee; Lieutenants Pierre Gustave Toutant Beauregard, Isaac I. Stevens, Zealous Bates Tower, Gustavus Woodson Smith, George B. McClellan, John Gray Foster.
Ordnance Department.
- Captain Benjamin Hugér, Chief, with siege train.
- First-Lieutenant Peter Valentine Hugner.
- Second-Lieutenant George Thom.
- Brevet Second-Lieutenant E.L.F. Hardcastle.
Quartermaster's Department.
Captains James R. Irwin, Chief; Abraham C. Myers, Robert Allen, Henry Constantine Wayne, Justus McKinstry, George W.F. Wood, J. Daniels, O'Hara, Samuel McGowan.
Subsistence Department.
- Captain John Breckinridge Grayson, Chief.
- Captain Thomas P. Randle.