Could Moat Cailin be rebuild or would it be easier to demolish the current structure and build a new castle? And what would the economy of the lands controlled by the lord of Moat Cailin be?

[Alex13]

I'm wondering how long it would take to rebuild Moat Cailin or to build a new castle on the same spot. I'm not referring to rebuilding/building the castle to the size it was before, but maybe ensure that it has 4-6 towers and a keep, all of it made of stone. How long might that take, if money would not be an issue and if the lord doing it, would either have a large amount of coin available or if he would have a steady stream on (a decent/large) income?

Also, considering the position of the castle and that the lands to the south are bogs and swamps and that i imagine that the lands to the north are solid ground, what might the economy of the lands look like? Would they be able to plant and harvest various produce, such as barley, oats, grain, possibly rice should they trade with a nation that uses it and should rice exist in ASOIAF, potatos, etc? And to also possibly have herds of sheep, ram or cows? Or would the area be (somewhat) poor and depend on the traffic of people/merchants travelling through the area?

I know that the location of the Moat is strategically important for the North's security and that the lord there could abuse his station, especially with regards to taxes on the merchants/people travelling to and from the North, but maybe the Lord of Winterfell could include in the feudal contract with the Lord of Moat Cailin, that they are not to raise the taxes without the approval of the Stark's, to avoid a situation similar to the one with the Frey's in the Riverlands, considering that the Frey's also control a strategic crossing.

And what military strength would the house controlling Moat Cailin and the lands around, have?

[Lady_Qohor]

I would imagine that the economy/resources of the land are pretty poor. It wouldn't take much to build a livable wooden keep and barracks within the walls. The fact that nobody seems to have settled in there for over a thousand years suggest that there is very good reason for people not wanting to live there on a long term basis. It may be there is not enough food or freshwater nearby to support a noble's household, or maybe there's a more sinister magical reason.

[Canon Claude]

It’s probably a good idea to keep the current structure and build a new castle further back on solid ground. That way, there will be a new defence of the Neck once the first one finally collapses.

I’d be tempted to say that House Reed should manage Moat Cailin, but they’re clearly not interested. Maybe once the wars are done, reward a loyal follower by elevating them to lord status?

[Trigger Warning]

It'd probably just be redundant, the towers already do the job that needs doing. 

[Canon Claude]

3 hours ago, Trigger Warning said:

It'd probably just be redundant, the towers already do the job that needs doing. 

But they’re going to fall over eventually. One of them is literally on its way down.

[Alex13]

Yeah, the Moat is decaying and sooner or later it will collapse entirely. It's strange that House Stark hasn't taken care of Moat Cailin across the years, considering that it serves a very important function in the defense of the North. 

[Trigger Warning]

10 hours ago, Canon Claude said:

But they’re going to fall over eventually. One of them is literally on its way down.

And they'll deal with it when it's nearly time, probably reuse the stone too and just make some similar towers. We're talking about towers that have existed on a timescale of thousands of years, definitely a problem for future people as far as anyone's concerned. 

[James Fenimore Cooper XXII]

Moat Cailin is surrounded by wetlands.  It is good for duck hunting but not for agriculture.  Suffice it to say that this area will have low revenues.  Moat Cailin can be rebuilt but the Starks and the Reeds will be hard pressed to find the coin to make that happen.  The north is poor.  Moat Cailin will take a lot of construction work.  House Reed will not have the financial resources to maintain the fortress. 

[Loose Bolt]

7 hours ago, Alex13 said:

It's strange that House Stark hasn't taken care of Moat Cailin across the years, considering that it serves a very important function in the defense of the North. 

If I were ruling king and I had found out that Starks are rebuilding MC my first idea would have been that they are planning of rebellion against me. After all by rebuilding that castle they would have made sending troops to North much harder. So it is possible that men sitting on Iron Throne did not allow Starks to do anything that would have made MC stronger. Or kings of Westeros wanted to keep MC and the North as weak as possible.

[Targaryeninkingslanding]

Depending on the terrain it may not be wise to build a larger stone fortress. In wetlands the ground can be really soft and so too heavy of a stone fortress could end up sinking. I think the main defense of the moat is meant to be the terrain, while it being weak to the north side is advantageous to Winterfell in keeping it for the North, like the wall. Financially it would probably be cheaper to try to repair or maintain the what's there, but militarily it makes sense to try to strengthen it with amenity between kingdoms.

[Alex13]

1 hour ago, Loose Bolt said:

If I were ruling king and I had found out that Starks are rebuilding MC my first idea would have been that they are planning of rebellion against me. After all by rebuilding that castle they would have made sending troops to North much harder. So it is possible that men sitting on Iron Throne did not allow Starks to do anything that would have made MC stronger. Or kings of Westeros wanted to keep MC and the North as weak as possible.

That makes sense, but it's also a bit strange.

I mean, the Bloody Gate in the Vale serves the same function, in that it protects the main road into the kingdom it is a part of. If an army would like to invade the Vale and if they would like to invade through the main road, then they would have to take the Bloody Gate and they would sustain high casualties doing that. The other options would be to take Gulltown, they fight the Royces of Runestone and then travel through mountain roads, where they could be attacked by the mountain clans. Or they could invade through the fjords in the east of the Vale. 

And the Golden Tooth of the Westerlands also serves a similar function, as an invading army would have to take the castle to gain further access into the Westerlands. In the books, Robb and the northern army are lucky and find a goat path that leads beneath the castle and they can bypass it. 

Plus, even as it currently stands, if properly garrisoned and supplied, Moat Cailin can be a formidable defensive structure. 

If the various kings sitting the Iron Throne wanted the North weaker and easier to invade, they could have asked/demanded that Moat Cailin be completely torn down.

[Trigger Warning]

42 minutes ago, Alex13 said:

If the various kings sitting the Iron Throne wanted the North weaker and easier to invade, they could have asked/demanded that Moat Cailin be completely torn down.

They probably didn't because ultimately it only makes the North slightly easier to assail, so long as the North can sit an army at the end of the causeway it's simply not practical to use it to invade. No point in raising tensions over something like that especially when you have dragons. 

[Alex13]

1 hour ago, Trigger Warning said:

They probably didn't because ultimately it only makes the North slightly easier to assail, so long as the North can sit an army at the end of the causeway it's simply not practical to use it to invade. No point in raising tensions over something like that especially when you have dragons. 

Yeah, but when they had dragons, they could have agreed to have the Stark's rebuild Moat Cailin and possibly have a house take control of the lands or have a garrison stationed permanently there, considering that they had dragons and the dragons canceled the advantage that the Moat gave.

[Trigger Warning]

5 hours ago, Alex13 said:

Yeah, but when they had dragons, they could have agreed to have the Stark's rebuild Moat Cailin and possibly have a house take control of the lands or have a garrison stationed permanently there, considering that they had dragons and the dragons canceled the advantage that the Moat gave.

So why bother with all that expense? They don't expect they'll be getting invaded any time soon considering the continent has been pacified by one dynasty and it won't even matter if they rise in rebellion since their overlords have dragons. Based on the information we have the towers do their job as they have done for thousands of years and likely will for hundreds if not thousands more, rebuilding the fortress and garrisoning it is a massive undertaking with no immediate benefit especially since the bottleneck the Neck creates is a monumental "natural" barrier in itself even without the Moat. 

They won't have to agree to it with the Starks because I doubt any Starks even want to take on the expense and hassle. 

[Moiraine Sedai]

It will take a long time to build from scratch.  It's faster to repair.  It will look suspicious from the south and will be taken as a north prepping for war.