Highest casualties in the first month of fighting

The Union (District of the Ohio) suffered slightly more casualties than the Confederates (District of Tennessee) in July 1861. The unit that suffered the most casualties during the month was the 2nd Kentucky Cavalry (US) with 303 casualties from constant skirmishing in the western sector of the campaign theater (Riverside, Orr Tavern, Newport, etc). The heaviest Confederate loss was in the 1st Tennessee Infantry, with 243 losses, largely suffered while trying to stop Colonel Solomon Lewis' advance on Madison during the the last week of July.

The cavalry on both sides suffered heavy losses from almost constant probing and skirmishing. Infantry also took similar losses, primarily along various towns on Kingston Road, although one Confederate brigade managed to go through the month with only minor casualties (less than 50 total).