The forces gathering under Gen. Forrest could prove to be a dire threat against our communications. I wrote Gen. Halleck,
HDQRS. MILITARY DIVISION OF THE MISSISSIPPI,
Nashville, Tennessee, December 23, 1863.
Major General H. W. HALLECK,
General-in-Chief, Washington, D. C.:
GENERAL: I am now collecting as large a cavalry force as can be spared at Savannah, Tennessee, to cross the Tennessee River and co-operate with the cavalry from Hurlbut’s command in clearing out entirely the forces now collecting in West Tennessee under Forrest. It is the design that this cavalry, after finishing the work they first start upon, shall push south through East Mississippi and destroy the Mobile road as far south as they can. Sherman goes to Memphis and Vicksburg in person, and will have Grenada visited and such other points on the Mississippi Central road as may require it. He will also take effectual measures to secure the quiet and safe navigation of the Mississippi.
I instructed McPherson to pay no attention to department or district limits in his operations against parties threatening the security of river navigation. It was not my desire to move against Mobile until the ends suggested in your dispatch are all secured. I want East Tennessee as far as Bristol free from any threat from a rebel force. I want West Tennessee and the State of Mississippi so visited that large armies cannot traverse there this winter, and would like to see the army in front of Chattanooga pushed farther south. This latter, however, I do not now expect to accomplish. The roads about Chattanooga have become perfectly impassable. This, however, obviates to a great extent the necessity for driving the enemy farther back at that point.
My advices from East Tennessee are not satisfactory. General Foster telegraphs me, however, that having no cipher he cannot telegraphs particulars as he otherwise would. If Longstreet retains his present position until the 28th, I shall leave Chattanooga on that day for Knoxville and the scene of operations in East Tennessee.
I am, general, very respectfully, &c.,
U. S. GRANT,
The Papers of Ulysses S Grant, Vol 9, p 551
O.R., I, xxxi, part 3, p 473