During the past year I've been examining the possibilities for regaining substantial parts of the state. At the end of March 1863, the eastern half of Kentucky was lightly held.
Rosecrans believed his cavalry to be outmanned by their Southern counterparts and waited on a more more favorable opportunity to advance in middle Tennessee. The arrival of Van Dorn's Cavalry Division and the ease with which it captured an isolated Federal brigade at Thompson's Station certainly tipped the balance. Confederate infantry brigades from Mobile, Atlanta and exchanged prisoners from Arkansas Post strengthened the Army of Tennessee, which far outgrew its size before the Battle of Murfreesboro until authorities stopped sending conscripts and recruits to Tennessee on April 10th.
Stevenson's Division was supposed to be returned to the Army of Tennessee. Instead Breckinridge's Division plus two brigades of McCown's old division received marching orders to Mississippi. Three good brigades from the coast of South Carolina were also ordered west, so the equivalent of two divisions were moved across the country for no good purpose. Van Dorn was killed by a jealous husband, and his cavalry returned to Mississippi, again for no good purpose.
Finally, the equivalent of four infantry brigades had been scattered across East Tennessee and SW Virginia. With the exception of Cumberland Gap, no detachment really strong enough to hold any one point. Another wasted division.
Counting Stevenson's Division, an infantry brigade which could have been assembled in SW Va. plus Evans' Brigade (soon returned to the Carolina coast), something like thirty-six infantry brigades were available. This is little different from the army assembled in north Georgia six months later without the need to call Longstreet from Lee's army. Leaving three divisions in middle Tennessee, those of Cleburne, Cheatham and Withers, which constituted the Army of Tennessee at the end of May 1863, six divisions or two corps were available to move via different routes into Kentucky and assemble in the central part of the state.
To lead these two Confederate corps into the Bluegrass, seven cavalry brigades were available. Three of these from Kentucky were led by Duke, Cluke and Giltner. Morgan's fine command would be lost after being captured in July, while Giltner's remained on outpost duty in SW Virginia. Scott's and Pegram's brigades had not been used for much more than occasional raids over the Tennessee line. These good mounted commands fought at Chickamauga, along with the brigades of Colonels Harrison and Crews from Wheeler's cavalry. These seven brigades could break up communications, capture outposts and screen Confederate infantry columns marching into the state.
What of major Federal commands in Kentucky? One of the Lincoln administration's war aims was the seizure of East Tennessee. To accomplish this, on March 15th Burnside's IX Corps of two divisions was ordered from the Atlantic coast cross-country to Cincinatti OH. Burnside's troops arrived slowly over the next three months. Two divisions of the XXIII Army Corps (organized in April 1863). Even with Morgan's Raid, the U.S. War Department felt comfortable enough with Kentucky to send two divisions of the IX Corps to General Grant at Vicksburg. These were returned late that summer to help occupy East Tennessee.
Even if all six Confederate divisions did not march into Kentucky at the same time, sufficient infantry would have been on hand to capture or rout several Federal brigades stationed in central Kentucky. Rosecrans would have been obliged to lead three of his four corps into the western half of the state to cover Louisville and protect rail communications with Nashville. The need to hold that city was such that Rosecrans would need to leave a sufficient garrison there, reducing his available force by 25% and removing any threat to middle Tennessee. The three remaining divisions of the Army of Tennessee -- Cheatham, Cleburne and Withers -- could then have moved via the Sequatchie Valley to join the other two corps then in middle Kentucky.
By then Forrest, having pursued and captured a Federal mounted command raiding through Alabama, could have been sent west across the Tennessee River with his own and Armstrong's Cavalry Brigade. A strike into that regions would have created at least as much concern as Forrest's Christmas raid a few months earlier. This was a fertile area for Confederate recruiting, while the U.S. War Department scrambled to find troops to send into West Tennessee, Forrest would have been increasing his force and seeking Federal outposts to strike. Enough divisions might have been diverted from either Grant or Banks for operations at either Vicksburg or Port Hudson to be suspended.
A battle like Chickamauga in the Bluegrass during late May or early June could have similar results. The defeat of Rosecrans would have forced the Lincoln administration to react exactly as they did after Chickamauga - detach the XI and XII Corps from the Army of Potomac, and send a strong force from Mississippi, the whole possibly to be led by Grant. Corinth might have been given up to achieve the desired results.
What if the Confederate army eventually had to leave Kentucky? What good would have resulted from all this? Many Confederate outposts and garrisons in East Tennessee could have reduced or eliminated in favor of active campaigning. This occured when Burnside occupied Cumberland Gap and Knoxville in August. Vicksburg, which was lost in July along wiath its entire garrison of 30,000, might not have been lost at all. On the other side of the line, U.S. garrisons at various points like Memphis, Nashville, Cairo, Louisville and Cincinatti, would have to be increased, thus reducing the active Federal force in the field. Chattanooga, Knoxville and probably even middle Tennessee would have remained in Confederate hands. Forrest would have returned from West Tennessee with a larger, better equipped command.
Another result would have been in favor of the Army of Northern Virginia. Detachment of the XI and XII Corps would have meant fewer Federal commands to contend with on the field at Gettysburg. It would not guarantee a Confederate victory on that battlefield, but certainly the odds would be more in Lee's favor.
Just something to consider.