National Road milestone 4 (4 M To B) is rather well hidden, almost part of a stone wall, often hidden by vines and brush. The content and style also distinguish it from many other milestones along the Road.
The M is rather small - about half the height of the numeral 4, and level with the top of that number. More interestingly, and unique to this stone, is, below the text, an arrow pointing in the direction of Baltimore. I only noticed this recently, but it is quite obvious, especially if you look at the detail below.
