Mike, This really opens up a "can of worms", because numbers vary greatly depending upon source. I took this directly from Gen. Grant's battle report. There is no way of us players knowing what source you are using (with all due respect, of course!). Grant said this: "The actual number of Confederates at Fort Donelson can never be given with entire accuracy. The largest number admitted by any writer on the Southern side, is by Colonel Preston Johnston. He gives the number at 17,000. But this must be an under-estimate. The commissary general of prisoners reported having issued rations to 14,623 Fort Donelson prisoners at Cairo, as they passed that point. General Pillow reported the killed and wounded at 2,000; but he had less opportunity of knowing the actual numbers than the officers of McClernand's division, for most of the killed and wounded fell outside their works, in front of that division, and were buried or cared for by Buckner after the surrender and when Pillow was a fugitive. It is known that Floyd and Pillow escaped during the night of the 15th, taking with them not less than 3,000 men. Forrest escaped with about 1,000 and others were leaving singly and in squads all night. It is probable that the Confederate force at Donelson, on the 15th of February, 1862, was 21,000 in round numbers." I will send you the link to this page in a separate e-mail.
Respectfully, RaggedRebel