...h a bridle, they would find a horse. From Leetown Johnson crossed the Potomac at Shepherdstown, passed rapidly through Sharpsburg to Boonsboro, on the 4th of July, leaving a large infantry force on Maryland Heights on his right and rear, depending on Early's infantry to take care of them. From Boonsboro he pressed down the National road through Middletown on Frederick. At Middletown he ran into a regiment o...