At the time of the fall of Forts Walker and Beauregard, Charleston harbor was defended by Forts Moultrie and Sumter, Castle Pinckney and Fort Johnson, and by batteries on Sullivan's and Morris islands. All these were to be strengthened, and the harbor made secure against any attack in front. To prevent the occupation of James island, the mouth of Stono river was defended by forts built on Cole's and Battery islands, and a line of defensive works built across the island. No attempt had been made to erect forts or batteries in defense of the inlets of Worth or South Edisto, but the harbor of Georgetown was protected by works unfinished on Cat and South islands, for twenty guns, the heaviest of which were 32-pounders.
When General Lee took command, November 8th, he established his headquarters at Coosawhatchie, and divided the line of defense into five military districts, from east to west, as follows: The First, from the North Carolina line to the South Santee, under Col. A. M. Manigault, Tenth volunteers, with headquarters at Georgetown; the Second, from the South Santee to the Stono, under Gen. R. S. Ripley, with headquarters at Charleston; the Third, from the Stono to the Ashepoo, under Gen. N. G. Evans, with headquarters at Adams' run; the Fourth, from Ashepoo to Port Royal entrance, under Gen. J. C. Pemberton, with headquarters at Coosawhatchie; the Fifth, the remainder of the line to the Savannah river, under Gen. T. F. Drayton, with headquarters at Hardeeville.
On the 27th of December, General Lee wrote to Governor Pickens that his movable force for the defense of the State, not including the garrisons of the forts at Georgetown and those of Moultrie, Sumter, Johnson, Castle Pinckney and the works for the defense of the approaches through Stono, Wappoo, etc., which could not be removed from their posts, amounted to 10,036 Confederate troops--the Fourth brigade, South Carolina militia, 1,531 strong; Colonel Martin's mounted regiment, 567 strong; two regiments from North Carolina, Clingman's and Radcliffe's; two regiments from Tennessee, the Eighth and Sixteenth, and Colonel Starke's Virginia regiment; the Tennesseeans and Virginians making a brigade under Brigadier-General Donelson. The above, with four field batteries, made up the force scattered from Charleston to the Savannah river, and stationed along the line, on the mainland, in front of the headquarters above named.