: : While Annuminas was a fair distance from the 'front lines'
: : (probably extending from the upper North Downs to the
: : confluence of the Greyflood, depending on the exact point in
: : time), it was undefended from any attack originating in the
: : north. The armies of Carn-Dum could have easily marched north
: : of the North Downs (skirting Fornost), through the wastelands
: : of northern Eriador, and southwest to Annuminas. Assuming the
: : Witch-king had enough sense to post a rearguard to the east to
: : prevent an attack by Arthedain, such a move could have been
: : made virtually uninhibited.

: Taking an army that far east would have been quite a feat. Even the Witch-king would still have to contend with supply-line problems, and the Dunedain of Fornost should have been able to attack him from the flank. But there would be no strategic advantage to attacking Annuminas and the Hills of Evendim. Any army sent there would be cut off from support, and it would not be in any better position to attack Fornost.

I certainly agree that there would be no strategic advantage to attacking Annuminas; such an attack would be more of a demoralizing move - i.e., raping the former Capitol of Arnor, destroying any fair works which might have remained and crushing the city of Elendil into ruins. I do not doubt such a plan would have appealed to the Witch-king. Of course, I am straying into the realm of conjecture here :)

: : Also, there do not seem to have been any walls or forts between
: : the North Downs and the Emyn Uial. And, since the Dunedain
: : where certainly capable of building large-scale fortifications
: : (as evidenced in the Hadrian-like wall built south of the
: : East-West Road to defend Cardolan), I can only assume that they
: : had no reason to do so. This would suggest to me that by the
: : time Angmar became a threat (ca. TA 1356), the area was of no
: : great military value, or contained nothing worth defending.

: Angmar wasn't as much of a threat at this time as it would later become, but 1356 was almost 500 years after the abandonment of Annuminas. Population in the region probably declined significantly after the city was abandoned. Certainly no one lived in the lands south of Annuminas in 1600 because Argeleb II ceded that region to the Hobbits.

: And, for what it's worth, I think the wall and dike were built by Arthedain to stop agression from Cardolan. The wall, at least, was on the north side of the dike. I wish we could decipher the name "Tyrn Gorthad". I feel like its meaning would shed some light on the history of the region. It wasn't just a burial region. Dunedain actually lived there in fortified towers. And shepherds lived there afterwards.

If the dike was indeed south of the wall, then I agree that it was probably built to provide a defense against Cardolan. I guess the point I was trying to make was that the Dunedain of Arthedain possessed the skill to create such works, and should it have been necessary, they could have built a similar wall between the North Downs and the Emyn Uial. However, it seems that they did not have the need to do so.

I'm still working on Tyrn Gorthad :)