Meade, George Gordon (1815-1872) [Standing orders for the first day of the Battle of Gettysburg]

Head Quarter Army of Potomac
Tarrytown July 1st 1863.
Circular
From information received the Commanding General is satisfied that the object of the movement of the Army in this direction has been accomplished viz., the relief of Harrisburgh and the prevention of the Enemy's intended invasion of Philadelphia &c beyond the Susquehanna.
It is no longer his intention to assume the offensive until the enemy's movement or position should render such an operation certain of success.
If the enemy assume the offensive and attack, it is his intention after holding them in check sufficiently long to withdraw the trains and other impediments - to withdraw the Army from its present position and form line of battle, with the left resting in the neighborhood of Middleburg and the right at Manchester, the general direction being that of Pipe Creek
For this purpose Gen'l Reynolds in command of the left will withdraw the force at present at Gettysburgh, two Corps by the roads to Tarrytown and Westminster and after crossing Pipe Creek, deploy towards Middleburg.
The Corps at Emmetsburg will be withdrawn via Mechanicsville to Middleburgh, or if a more direct route can be found leaving Tarrytown to their left, to withdraw direct to Middleburg.
Gen'l Slocum will assume command of the two Corps at Hanover and Two Taverns, and withdraw them via Union Mills, deploying one to the right and one to the left after crossing Pipe Creek, connecting on the left with Gen'l Reynolds, and communicating his right to Gen'l Sedgwick at Manchester who will connect with him and form the right.
The time for falling back can only be developed by circumstances; when [2] ever such circumstances arise as would seem to indicate the necessity of falling back and assuming this general line indicated notice of such movement will be at once communicated to these Head Quarters and to all adjoining Corps Commanders.
The 2nd Corps now at Tarrytown will be held in reserve in the vicinity of Uniontown and Frizzleburgh to be thrown to the point of strongest attack, should the enemy make it. In the event of these movements being necessary, the trains and impediments will all be sent to the rear of Westminster.
Corps Commanders with their Officers Comdg Artillery and the Divisions should make themselves thoroughly familiar with the country indicated, all the roads and positions - so that no possible confusion can ensue, and that the movement, if made, be done with good order, precision and care, without loss, or any detriment to the morale of the troops.
The Commanders of Corps are requested to communicate at once the nature of their present positions and their ability to hold them in case of any sudden attack at any point by the Enemy.
This order is communicated that a general plan perfectly understood by all, may be had for receiving attack if made in strong force upon any portion of our present position.
Developments may cause the Commanding General to assume the offensive from his present position.
The Artillery reserve will in the event of the general movement indicated, move to the rear of Fizzleburgh and be placed in positions, or sent to Corps as circumstances may require, under the general supervision of Chief of Artillery.
The Chief Quartermaster will in case of the general movement indicated, give directions for the orderly and proper position of the trains in rear of Westminster.
All trains will keep well to the right of the road in moving, and in case of any accident requiring a halt, the [train] [3] must be hauled out of the line and not delay the movements.
The trains ordered to Union Bridge in these events will be sent to Westminster.
General Head Quarters will be, in case of this movement, at Frizzleburgh, Gen'l Slocum as near Union Mills as the line will render best for him.
General Reynolds at or near the road from Tarrytown to Frizzleburgh
The Chief of Artillery will examine the line and select positions for Artillery.
The Cavalry will be held on the right and left flanks, after the movement is completed; previous to its completion he will as now directed, cover the front and exterior lines well out. The commands must be prepared for a movement and in the event of the enemy attacking us on the ground indicated herein, to follow up any repulse.
The Chief Signal Officer will examine the line thoroughly, and at once upon the commencement of this movement extend telegraphic communication from each of the following points to Gen'l Head Quarter near Frizzleburgh. viz., - Manchester, Union Mills, Middleburg and the Tarrytown Roads.
All true Union people should be advised to harass and annoy the Enemy in every way - to send in such information and taught how to do it: - giving Regiments by number of Colors - number of Guns, General's names &c.,
All their supplies brought to us will be paid for, and not fall into the enemy's hands.
Roads and ways to move to the right or left of the general line should be studied, and thoroughly understood. All movements of troops should be concealed and our dispositions kept from the Enemy.
Their knowledge of these dispositions would be fatal to our success, and the greatest care must be taken to prevent such an occurrence.
By Command of Maj. Gen'l Meade
(signals) S. Williams
A. A. G.

[docket and notes on page 4]