You are aware that in most cities there are prisons?

The cities of Stormhold and Gideon were originally founded by the Ayleids (their Ayleid names are unknown), but were so far removed from their culture in the heartland that they never were attacked by the Alessian army when it rose in revolt.

Stormhold, Black Marsh

True to its name, it was forever raining in Stormhold. The water soaked the very stone itself, seeping into cracks and mortar, so even the interior of the Mages Guild was damp, musty. The Guild itself was composed of nothing but Argonians of a majestic variety, tall and crowned with scaled hoods, horns, spikes, and frills. Their skin were jewelry, male and female alike, flashing blues, greens, reds, orange, and sparkling black.

'Welcome to Stormhold,' the mystic in charge of teleportation, a ruby-colored female Argonian called Seven-Stars greeted each person as he or she arrived. 'I have not been told why you seek it, but the Vaults of Gemin are to the south. If you are lucky, but a few hours away. An infinite distance if your luck is not with you.'

Stormhold was a city of enormous size, set on stilts with covered bridges linking block to block. Beneath it all a black swamp surged and hissed, constantly fed by the rain, flowing southward.

A few miles in any direction, the rain would reduce to a mere mist, but never less than that. It was green, but a pale green, from constant sunless days. The air was heavy, and though some of the swamp flowers had sweet perfumes to lure, it was hard to avoid the pervasive smell of decay.

Whatever lurked in the slow-moving waters between the mud, perhaps it was best not to imagine.

The description of Stormhold is of a city suspended above a vast swamp and under constant rainstorms. Bridges are slung like spider webs between huge trees and stone buildings on stilts (presumably not wooden stilts-- such couldn't support the weight and also sit rotting in a bog). Noteworthy is the mention of three Hist trees in Stormhold alone, countering speculation by some fans that only one Hist still lives. Also there's the description of Argonians in many different, non-green colors; something not seen in extant lore. He also indicates that most of the city is underwater and the Argonians have no trouble breathing water, which runs counter to the limited racial ability seen in TES 3: Morrowind. Most unusual is the description of some form of Argonian called a "naga". These are huge, over 7 foot tall Argonians with beady black eyes, venomous fangs, and the odd ability to get ...puffier?

The only reference I can find is in the PGE3, in the section on Blackmarsh.



And found some stuff in the Argoninan Compendium. It seems that during an RP Tedders once wrote a short description of Stormhold. Since Tedders wrote the PGE3 and a lot of ingame books this can be considered canon in a way. Also some elements of another RP became canon.
And from Bredan, the author of the Argonian Compendium:
From: http://www.imperial-library.info/fsg/brendanarticle1.shtml