Formerly a drow stronghold, located in the Underdark more or less directly beneath Darkot, it was the dark elves’ largest city in the region, only slightly smaller than the actual Menzoborranzen near Faerun’s Sword Coast. It was, in fact, constructed almost identically to Menzoborranzen, featuring the same tall, nearly unscalable walls, the same pillars of light, the same general geographic layout, the same locations of key monuments, sites or buildings, the same, in other words, everything.
At their goddess Lloth’s behest, he drow of Neo Menzoborranzen pursued the Helm of Sesyphus with deliberate intent during the first campaign. They even conquered the capital city of Darkot for a short time. Sadly for them, that was the last great thing they would ever accomplish.
The history of the War With the Drow is well documented, so shall not be recounted here. Suffice to say that after Darkot attacked this city in an effort to flush the dark elves out of their home, the duergar of nearby Beldor laid seige to Neo Menzoborranzen. The seige did not last long, for the githzerai of Limbo saw an opportunity. They were led by one of the Unlikely Darkotians, Slattern Sespot. Under Slattern’s direction, the Gith attacked Beldor, inflicting great damage on it. When it was clear they would eventually win a war with the duergar, they negotiated an end to Beldor’s siege of Neo Menzoborranzen. Because that had always been Slattern’s true target. The drow were still weakened after their war with Darkot, as well as by a budding civil war, caused by the Rod of Drow Bane, they were still trying to squash. It didn’t take long for Slattern’s gith army to completely sack the city.
All of that means there are no longer drow in Neo Menzoborranzen. For now, the gith have kept the name as they rebuild the city to more closely match their culture and purposes. Devastated by a war, a seige and then a second war, it has taken the city some time to establish itself as a destination for merchants, but it is starting to make a come back. It serves as something of a sister city to the Golan Depths.