Government:
Semi-Democratic Oligarchy
Nyhmorarch
Four Archons of the Seasons
Summer - Polemarch
Spring, Autumn, Winter - Eponymous Archons
Blessings Tree:
History and Legends meshed into one, claiming that the Blessings Tree is a gift from the gods, a seed that was given to the first people in the region to care for. They were taught how to shape it without harming it and how to encourage its growth. After millennia of this magic slowly shaping the tree into a hub of life, housing council halls, markets, and more within, the tree sings with magic. Furthering this influence, a Forge of Creation lies amongst its roots, though many have forgotten of its existence. While it's not currently operational, its continued existence prevents leaving a space in reality that will be filled by something else.
Over time, the Blessings Tree had shoots sprout from its roots throughout the vale, providing its inhabitants with homes they could shape for themselves.
Because of the nature of their architecture, Feywilders who have magic that's closely tied to emotion are taught from a young age to control themselves so their magic wouldn't harm the Tree or its offspring.
The Blessings Tree functions as a sort of magical translator, allowing people who speak different languages to understand one another easily. It could be likened to a powerful, AOE comprehend languages spell.
Geography:
Nestled within the Misty Giants Mountains, Knashthra lay hidden behind illusions and wards. The paths that lead travelers through the mountains and into the vale are expertly hidden, the magic keeping them so fueled by the Blessings Tree and Knashthra's inhabitants. The weather is varied, perfectly demonstrating the best and worst of each season just as the Knashthrans themselves do. A wide river flows from the Northeast to the Southeast, the source from a spring at the base of one of the many snow topped mountains. It ended in a deep pool, though where the water went from there was unknown. The amount of water that poured from the spring was enough to irrigate the fields and the land was fertile for farming. Whether it was the magic of the Feywild, the Blessings Tree, the soil's natural state, or something else, Knashthrans weren't quite sure, but they didn't question it. They thank the gods for the bounty, and on the spring equinox, they celebrated the beginning of a new, bountiful year and shared all they had with one another. Most of the largest plants in the region are the shoots from the Blessings Tree that were grown and shaped into homes and shops.
On the whole, it is a picturesque nation, seeming almost perfect.
But not quite.
Customs:
Death:
They call those they're close to and believe will take their death the hardest their Gardeners. The Gardener's role is to plan a garden over the deceased's grave; it can be flowers, a single tree, or a rock garden, but it has to be something they can tend to. The thinking behind it is that it gives those grieving the hardest a chance to heal and accept the loss. By giving them a life to tend to, it forces them to leave their homes and keep themselves busy, to help them find life in death. It's practiced by about three-quarters of the population these days.
Locations of the Fey Crossroads from Faerûn to the Feywild are located in:
The Neverwinter Wood outside the city of Neverwinter
Myth Dranor/Knashthra
Until/unless J says otherwise, I'm placing a few here since DnD canon is unclear about exact locations. They're described in being out-of-the-way or hard-to-reach places, sometimes where no sapient beings but the fey have walked, sometimes where great tragedy took place, sometimes it's as simple as a random fairy circle that popped up after it rained a week ago.
Old Sharandar
The Cloud Peaks
Near Candlekeep (formerly, portal destroyed during the Spellplague)
Methwood (formerly, portal destroyed during the Spellplague)
Planes of Purple Dust
Eastern side of the Thunder Peaks (active)
The Great Glaciers (unknown if active, or exact location)
Ice Spires