The Shire - boundary

Folks, what do we know of the boundary of the Shire? I know in the east its boundry is the Brandywine river, and Buckland is separated from the Old Forest by a great hedge, but the rest of the boundary of the Shire, appears non existent, geographically/topographically, other than a line on a map.

And yet, we know the boundary is kept watch over by the Shire Bounders, who "beat the bounds", so they must know the boundary area.

Can we assume the Shire is surrounded by a fence or hedge? Or perhaps in parts a stockade as at Bree?

Or is it quite simply cultivated land that gradually peters out into wilderness...

I welcome your thoughts and any references you may be able to point me to.

regards
Scott

I'd imagine there'd be mossy, overgrown marker-stones, probably inscribed with runes and reliefs that explain their purpose.

You can find plenty of free shire maps around that present the borders. The West border is generally accepted to be the Tower Hills, and the Northern boundary is around Lake Evendim and Annuminas, the Southern border isn't well defined, though considered to be the Southern Marshes.

http://www.shirepost.com/ShireMapLarge.html

Tower Hills is the Western Boundary of the Westmarch. Western boundary of the Shire proper is the the Far Downs.
For the Southern boundary read the South Farthing article notes.

Most maps for Middle earth I see now days seem off. I don't know why but...
Encyclepedia of Arda's map of the Shire for example has the Great Road terminated at Michel Delving (although they admit that it ternimates at Mithlond). I have always assumed the East/West Road was the northern boundary as it went on to Mithlond. And the Elves and Dwarves had little contact. Which seems odd as there was a reasonable amount of traffic of elves between Lindon and Rivendel and additional traffic of dwarves after the events of "The Hobbit". And the way that 12 dwarf families that indicate they should go out of their way to visit Bilbo Baggins in the Shire.