A large portion of Kentucky’s citizenry stayed neutral in the war, but 100,000 men went North, while another 35,000 went South. Almost all Kentuckians fought in the Western theater, but one Union light artillery battery did end up in the East, where they fought several battles in northern Virginia before being assigned to the defense of Washington.
I know there were Ky units fighting for both sides at Murfreesboro, TN - do you know if they fought directly against each other though? I got that impression from somewhere, but it's a hazy recollection...