Organization of the Division of the Potomac, August 4, 1861.

Brigadier-General Hunter's brigade.-Twenty-third, Twenty-fifth, Thirty-fifth, and Thirty-seventh Regiments New York Volunteers.

Brigadier-General Heintzelman's brigade.-Fifth Regiment Maine Volunteers, Sixteenth, Twenty-sixth, and Twenty-seventh Regiments New York Volunteers, and Tidball's battery (A), Second U. S. Artillery.

Brig. Gen. W. T. Sherman's brigade.-Ninth and Fourteenth Regiments Massachusett's Volunteers, De Kalb [Forty-first] Regiment New York Volunteers, Fourth Regiment Michigan Volunteers, Hamilton's battery (E), Third U. S. Artillery, and Company I, Second U. S. Cavalry.

Brigadier-General Kearny's brigade.-First, Second, and Third Regiments New Jersey Volunteers, Greene's battery (G), Second U. S. Artillery, and Company G, Second U. S. Cavalry.

Brigadier-General Hooker's brigade First and Eleventh Regiments Massachusetts Volunteers, Second Regiment New Hampshire Volunteers, and Twenty-sixth Regiment Pennsylvania Volunteers.

Colonel Keyes' brigade.-Twenty-second, Twenty-fourth, and Thirtieth Regiments New York Volunteers, and Fourteenth Regiment New York State Militia [Eightyfourth Volunteers].

Brigadier-General Franklin's brigade.-Fifteenth, Eighteenth, Thirty-first, and ThirtySecond Regiments New York Volunteers, Platt's battery (M), Second U. S. Artillery, and Company C[First], New York (Lincoln) Cavalry.

Colonel Blenker's brigade.-Eighth and Twenty-ninth Regiments New York Volunteers, Twenty-seventh Regiment Pennsylvania Volunteers, and Garibaldi Guard [Thirty-ninth], New York Volunteers.

Colonel Richardson's brigade.-Twelfth Regiment New York Volunteers and Second and Third Regiments Michigan Volunteers.

Brigadier-General Stone's brigade.-Thirty-fourth and Tammany [Forty-second] Regiments New York Volunteers, First Regiment Minnesota Volunteers, and Second Regiment New York State Militia [Eighty-second Volunteers].

Col. William F. Smith's brigade.-Second and Third Regiments Vermont Volunteers, Sixth Regiment Maine Volunteers, Thirty-third Regiment New York Volunteers, Company H, Second U. S. Cavalry, and Captain Mott's New York battery.

Colonel Couch's brigade.-Second Regiment Rhode Island Volunteers, Seventh and Tenth Regiments Massachusetts Volunteers, and Thirty-sixth Regiment New York Volunteers.

The Second Regiment Maine, the Second Regiment Wisconsin, and the Thirteenth Regiment New York Volunteers, stationed at Fort Corcoran.

The Twenty-first Regiment New York Volunteers, stationed at Fort Runyon. The Seventeenth Regiment New York Volunteers, stationed at Fort Ellsworth.

By October the new levies had arrived in sufficient numbers, and the process of organization so far carried on that the construction of divisions had been effected.

The following statement exhibits the composition of the Army, October 15, 1861:

Organization of the Army of the Potomac, October 15, 1861.

1. Brig. Gen. George Stoneman's cavalry command.-Fifth U. S. Cavalry, Fourth Pennsylvania Cavalry, Oneida Cavalry (first company), Eleventh Pennsylvania Cavalry (Harlan's), and Barker's Illinois Cavalry (one company).

2. Col. H. J. Hunt's artillery reserve.-Batteries L, A, and B, Second U. S. Artillery; Batteries K and F, Third U. S. Artillery; Battery K, Fourth U. S. Artillery; Battery H, First U. S. Artillery, and Battery A, Fifth U. S. Artillery.

3. CITY GUARD, BRIG. GEN. ANDREW PORTER.

Cavalry. Companies A and E, Fourth U. S. Cavalry.
Artillery.-Battery K, Fifth U. S. Artillery.

Infantry.-Second and Third battalions U. S. Infantry, Company - Eighth and Company-First U. S. Infantry, and Sturges' rifles (Illinois Volunteers).

4. BANKS' DIVISION.

Cavalry.-Four companies Third Regiment New York Cavalry (Van Alen's). Artillery.-Best's battery (F), Fourth U. S. Artillery; detachment Ninth New York

Artillery; Matthews' battery (F), First Pennsylvania Artillery; Tompkins' battery (A), First Rhode Island Artillery.

Infantry-Abercrombie's brigade: Twelfth Massachusetts, Twelfth and Sixteenth Indiana, and Thirtieth Pennsylvania Volunteers. Stiles' brigade: Third Wisconsin, Twenty-ninth Pennsylvania, and Thirteenth Massachusetts Volunteers, and Ninth New York State Militia [Eighty-third Volunteers]. Gordon's brigade: Second Massachusetts, Twenty-eighth and Nineteenth New York, Fifth Connecticut, Forty-sixth and Twenty-eighth Pennsylvania, and First Maryland Volunteers.

M'DOWELL'S DIVISION.

Cavalry.-Second New York Cavalry (Harris' Light), Colonel Davies.
Artillery.-Battery M, Second, and Battery G, First, U. S. Artillery.

Infantry.-Keyes' brigade: Fourteenth New York State Militia [Eighty-fourth Volunteers], and Twenty-second, Twenty-fourth, and Thirtieth New York Volunteers. Wadsworth's brigade: Twelfth, Twenty-first, Twenty-third, and Thirty-fifth New York Volunteers. King's brigade: Second, Sixth, and Seventh Wisconsin, and Nineteenth Indiana Volunteers.

HEINTZELMAN'S DIVISION.

Cavalry.-First New Jersey Cavalry, Colonel Halsted.
Artillery.-Thompson's battery (G), U. S. Artillery.

Infantry.-Richardson's brigade: Second, Third, and Fifth Michigan, and Thirtyseventh New York Volunteers. Sedgwick's brigade: Third and Fourth Maine and Thirty-eighth and Fortieth New York Volunteers. Jameson's brigade: Thirty-second, Sixty-third, Sixty-first, and Forty-fifth Pennsylvania Volunteers, and Wild Cat Reserves (Pennsylvania Volunteers).

F. J. PORTER'S DIVISION.

Calvary. Third Pennsylvania Cavalry, Colonel Averell, and Eighth Pennsylvania Cavalry, Colonel Gregg.

Artillery-Battery E, Second, and Battery E, Third, U. S. Artillery.

Infantry.-Morell's brigade: Thirty-third Pennsylvania, Fourth Michigan, Ninth Massachusetts, and Fourth New York Volunteers. Martindale's brigade: Thirteenth New York, Second Maine, and Eighteenth Massachusetts Volunteers, and De Kalb [Forty-first] Regiment New York Volunteers. Butterfield's brigade: Fiftieth New York, Eighty-third Pennsylvania, Seventeenth and Twenty-fifth New York Volunteers, and Stockton's Independent Michigan [Sixteenth] Regiment.

FRANKLIN'S DIVISION

Cavalry.-First New York Cavalry, Colonel McReynolds.

Artillery.-Batteries D and G, Second U. S. Artillery, and Hexamer's battery (Now Jersey Volunteers).

Infantry.-Kearny's brigade: First, Second, Third, and Fourth New Jersey Volunteers. Slocum's brigade: Sixteenth, Twenty-sixth, and Twenty-seventh New York, and Fifth Maine Volunteers. Newton's brigade: Fifteenth, Eighteenth, Thirty-first, and Thirty-second New York Volunteers.

STONE'S DIVISION.

Cavalry.-Six companies Third New York (Van Alen) Cavalry.

Artillery.-Kirby's battery (I), First United States; Vaughn's battery (B), First Rhodo Island Artillery, and Bunting's Sixth New York Independent Battery. Infantry.-Gorman's brigade: Second New York State Militia [Eighty-second Volunteers], First Minnesota, Fifteenth Massachusetts, and Thirty-fourth New York Volunteers, and Tammany [Forty-second] Regiment New York Volunteers. Lander's brigade: Nineteenth and Twentieth Massachusetts, and Seventh Michigan Volunteers, and a company of Massachusetts Sharpshooters. Baker's brigado: Pennsylvania Volunteers (First, Second, and Third California).

BUELL'S DIVISION.

Artillery.-Batteries D and H, First Pennsylvania Artillery.

Infantry.-Couch's brigade: Second Rhode Island, Seventh and Tenth Massachusetts, and Thirty-sixth New York Volunteers. Graham's brigade: Twenty-third and

Thirty-first Pennsylvania, and Sixty-seventh (First Long Island) and Sixty-fifth (First U. S. Chasseurs) New York Volunteers. Peck's brigade: Thirteenth and Twenty-first Pennsylvania and Sixty-second (Anderson Zouaves) and Fifty-fifth New York Volunteers.

M'CALL'S DIVISION.

Cavalry.-First Pennsylvania Reserve Cavalry, Colonel Bayard,

Artillery.-Easton's battery (A), Cooper's battery (B), and Kerns' battery (G), First Pennsylvania Artillery.

brigade:

Infantry.-Meade's brigade: First Rifles, Pennsylvania Reserves, Fourth, Third, Seventh, Eleventh, and Second Pennsylvania Reserve Infantry. Fifth, First, and Eighth Pennsylvania Reserve Infantry, Sixth, Ninth, and Twelfth Pennsylvania Reserve Infantry.

brigade: Tenth,

HOOKER'S DIVISION.

Cavalry.-Eight companies Third Indiana Cavalry, Lieutenant-Colonel Carter.
Artillery.-Elder's battery (E), First U. S. Artillery.

Infantry.- brigade: First and Eleventh Massachusetts, Second New Hampshire, Twenty-sixth Pennsylvania, and First Michigan Volunteers. Sickles' brigade: First, Second, Third, Fourth, and Fifth Regiments Excelsior Brigade [Seventieth, Seventy-first, Seventy-second, Seventy-third, and Seventy-fourth], New York Vol

unteers.

BLENKER'S BRIGADE.

Cavalry.-Fourth New York Cavalry (mounted rifles), Colonel Dickel.

Infantry.-Eighth and Twenty-ninth New York, Twenty-seventh and Thirty-fifth Pennsylvania Volunteers, Garibaldi Guard, and Cameron Rifles ([Thirty-ninth and Sixty-eighth] New York Volunteers).

SMITH'S DIVISION.

Cavalry,-Fifth Pennsylvania Cavalry (Cameron Dragoons), Colonel Friedman. Artillery.-Ayres' battery (F), Fifth U. S. Artillery; Mott's Second New York Independent battery, and Barr's battery (E), First Pennsylvania Artillery,

Infantry.- brigade: Second, Third, Fourth, and Fifth Vermont Volunteers. Stevens' brigade: Thirty-third and Forty-ninth New York and Sixth Maine Volunteers, and Seventy-ninth New York State Militia [Seventy-ninth Volunteers]. Hancock's brigade: Forty-seventh and Forty-ninth Pennsylvania, Forty-third New York, and Fifth Wisconsin Volunteers. Companies B and E, Berdan Sharpshooters.

Casey's Provisional Brigades.-Fifth, Sixth, and Seventh New Jersey Volunteers, Roundhead Regiment ([One hundredth] Pennsylvania Volunteers), Battalion District of Columbia Volunteers, Fortieth Pennsylvania, Eighth New Jersey, and Fourth New Hampshire Volunteers.

5. GARRISONS.

Alexandria.-Brigadier-General Montgomery, military governor. Cameron Guard ([Eighty-eighth] Pennsylvania. Volunteers).

Fort Albany.-Fourteenth Massachusetts Volunteers.

Fort Richardson. -Fourth Connecticut Volunteers.

Fort Washington. Company D, First U. S. Artillery; Companies H and I, Thirtyseventh New York Volunteers, and United States recruits unassigned.

6. DIX'S DIVISION, BALTIMORE.

Cavalry.-Company of Pennsylvania cavalry.

Artillery.-Battery I, Second U. S. Artillery, Second Massachusetts Light Battery, and a battery of New York artillery.

Infantry.-Third, Fourth, and Fifth New York, Seventeenth and Twenty-fifth Massachusetts, Twenty-first Indiana, Sixth Michigan, Fourth Wisconsin, Seventh Maine, Second Maryland Battalion, and Reading City Guard, volunteers.

[Battery E, Third U. S. Artillery, the Seventy-ninth New York State Militia, the Forty-seventh Pennsylvania Volunteers, and the Roundhead Regiment were transferred to General Sherman's expedition.]

2 R R-VOL V

On the 8th of March, 1862, the President directed, by the following order, the organization of the active portion of the Army of the Potomac into four army corps, and the formation of a fifth corps from the divisions of Banks and Shields.

The following is the text of the President's order:

PRESIDENT'S GENERAL WAR ORDER,

No. 2.

EXECUTIVE MANSION,
Washington, March 8, 1862.

Ordered, 1. That the major-general commanding the Army of the Potomac proceed forthwith to organize that part of the said army destined to enter upon active operations (including the reserve, but excluding the troops to be left in the fortifications about Washington) into four army corps, to be commanded according to seniority of rank, as follows:

First Corps to consist of four divisions, and to be commanded by Maj. Gen. I. McDowell.

Second Corps to consist of three divisions, and to be commanded by Brig. Gen. E. V. Sumner.

Third Corps to consist of three divisions, and to be commanded by Brig. Gen S. P. Heintzelman.

Fourth Corps to consist of three divisions, and to be commanded by Brig. Gen. E. D. Keyes.

2. That the divisions now commanded by the officers above assigned to the commands of army corps shall be embraced in and form part of their respective corps.

3. The forces left for the defense of Washington will be placed in command of Brig. Gen. James S. Wadsworth, who shall also be military governor of the District of Columbia.

4. That this order be executed with such promptness and dispatch as not to delay the commencement of the operations already directed to be undertaken by the Army of the Potomac.

5. A fifth army corps, to be commanded by Maj. Gen. N. P. Banks, will be formed from his own and General Shields' (late General Lander's) divisions.

ABRAHAM LINCOLN.

The following order, which was made as soon as circumstances permitted, exhibits the steps taken to carry out the requirements of the President's War Order, No. 2:

GENERAL ORDERS,

No.

HEADQUARTERS ARMY OF THE POTOMAC,
Fairfax Court-House, Va., March 13, 1862.

In compliance with the President's War Order, No. 2, of March 8, 1862, the active portion of the Army of the Potomac is formed into army corps, as follows:

First Corps, Maj. Gen. Irvin McDowell, to consist for the present of the divisions of Franklin, McCall, and King.

Second Corps, Brig. Gen. E. V. Sumner; divisions, Richardson, Blenker, and Sedgwick.

Third Corps, Brig. Gen. S. P. Heintzelman; divisions, F. J. Porter, Hooker, and Hamilton.

Sub

Fourth Corps, Brig. Gen. E. D. Keyes; divisions, Couch, Smith, and Casey. Fifth Corps, Maj. Gen. N. P. Banks; divisions, Williams and Shields. The cavalry regiments attached to divisions will for the present remain so. sequent orders will provide for these regiments, as well as for the reserve artillery, regular infantry, and regular cavalry. Arrangements will be made to unite the divisions of each army corps as promptly as possible.

The commanders of divisions will at once report in person, or, where that is impossible, by letter to the commander of their army corps. By command of Major-General McClellan :

A. V. COLBURN, Assistant Adjutant-General.

I add a statement of the organization and composition of the troops on April 1, commencing with the portion of the Army of the Potomac which went to the Peninsula, giving afterwards the regiments and batteries left on the Potomac and in Maryland and Virginia after April 1, 1862:

Troops of the Army of the Potomac sent to the Peninsula in March and early in April, 1862.

1st. Cavalry reserve, Brig. Gen. P. St. G. Cooke.-Emory's brigade: Fifth U. S. Cavalry; Sixth U. S. Cavalry; Sixth Pennsylvania Cavalry. Blake's brigade: First U. S. Cavalry; Eighth Pennsylvania Cavalry; Barker's squadron Illinois cavalry. 24. Artillery reserve, Col. Henry J. Hunt: Graham's battery (K and G), First U. S., six Napoleon guns; Randol's battery (E), First U. S., six Napoleon guns; Carlisle's battery (E), Second U. S., six 20-pounder Parrott guns; Robertson's battery, Second U. S., six 3-inch ordnance guns; Benson's battery (M), Second U. S., six 3-inch ordnance guns; Tidball's battery (A), Second U. S., six 3-inch ordnance guns; Edwards' battery (L and M), Third U. S., six 10-pounder Parrott guns; Gibson's battery (C and G), Third U. S., six 3-inch ordnance guns; Livingston's battery (F and K), Third U. S., four 10-pounder Parrottguns; Howe's battery (G), Fourth U. S., six Napoleon guns; De Russy's battery (K), Fourth U. S., six Napoleon guns; Weed's battery (1), Fifth Ú. S., six 3-inch ordnance guns; Smead's battery (K), Fifth U.S, four Napoleon guns; Ames' battery (A), Fifth U. S., six (four 10-pounder Parrott and two Napoleon) guns; Diedrich's battery (A), New York artillery battalion, six 20-pounder Parrott guns; Voegelie's battery (B), New York artillery battalion, four 20-pounder Parrott guns; Knieriem's battery (C), New York artillery battalion, four 20-pounder Parrott gans; Grim's battery (D), New York artillery battalion, six 32-pounder howitzer guns; total, 100 guns.

3d. Volunteer engineer troops, General Woodbury: Fifteenth New York Volunteers, Fiftieth New York Volunteers. Regular engineer troops, Captain Duane: Companies A, B, and C, U. S. Engineers. Artillery troops, with siege trains: First Connecticut Heavy Artillery, Colonel Tyler.

4th. Infantry reserve (regular brigade), General Sykes: Nine companies Second U. S. Infantry, seven companies Third U. S. Infantry, ten companies Fourth U. S. Infantry, ten companies Sixth U. S. Infantry, eight companies Tenth and Seventeenth U. S. Infantry, six companies Eleventh U. S. Infantry, eight companies Twelfth U. S. Infantry, nine companies Fourteenth U. S. Infantry, and Fifth New York Volunteers, Colonel Warren.

SECOND CORPS, GENERAL SUMNER.

Cavalry.-Eighth Illinois Cavalry, Colonel Farnsworth, and one squadron Sixth New York Cavalry. RICHARDSON'S DIVISION.

Artillery.-Clarke's battery (A and C), Fourth U. S., six Napoleon guns; Frank's battery (G), First New York, six 10-pounder Parrott guns; Pettit's battery (B), First New York, six 10-pounder Parrott guns; Hogan's battery (A), Second New York, six 10-pounder Parrott guns.

Infantry.-Howard's brigade: Fifth New Hampshire, Eighty-first Pennsylvania, and Sixty-first and Sixty-fourth New York Volunteers. Meagher's brigado: Sixtyninth, Sixty-third, and Eighty-eighth New York Volunteers. French's brigade: Fifty-second, Fifty-seventh, and Sixty-sixth New York and Fifty-third Pennsylvania Volunteers.

SEDGWICK'S DIVISION.

Artillery.-Kirby's battery (I), First U. S., six Napoleon guns; Tompkins' battery (A), First Rhode Island, six (four 10-pounder Parrott and two 12-pounder howitzer) guns; Bartlett's battery (B), First Rhode Island, six (four 10-pounder Parrott and two 12-pounder howitzer) guns; Owen's battery (G), six 3-inch ordnance guns.

Infantry.-Gorman's brigade: Second New York State Militia, Fifteenth Massachusetts, Thirty-fourth New York, and First Minnesota Volunteers. Burns' brigade: Sixty-ninth, Seventy-first, Seventy-second, and One hundred and sixth Pennsylvania Volunteers. Dana's brigade: Nineteenth and Twentieth Massachusetts, Seventh Michigan, and Forty-second New York Volunteers.

NOTE.-Blenker's division detached, and assigned to the Mountain Department.

THIRD CORPS, GENERAL HEINTZELMAN.

Cavalry.-Third Pennsylvania Cavalry, Colonel Averell.

PORTER'S DIVISION.

Artillery.-Griffin's battery (D), Fifth U. S., six 10-pounder Parrott guns; Weeden's battery (C), Rhode Island; Martin's battery (C), Massachusetts, six Napoleon guns; Allen's battery (E), Massachusetts, six 3-inch ordnance guns.