Gensokyo was originally a desolate, haunted region of Japan ages ago. The youkai that lived there began to terrorize the surrounding lands, and thus powerful, heroic humans were sent to exorcise and exterminate them. The off and on battle between humans and youkai continued on until 1885 A.D., when Gensokyo was sealed off from this increasingly scientific and skeptical world with the creation of the Great Hakurei Barrier. There has been little contact between those societies ever since. Today, the only known gateway between Gensokyo and this world is the Hakurei Shrine, which stands in isolation along the border on distant mountains of the far east. It's known that the local language spoken in Gensokyo is modern Japanese.
Gensokyo is populated mainly by youkai, but a decent human and rabbit population lives there as well. Some of its inhabitants went there to hide, to escape, to find shelter when no-one and nowhere else would accept them. Many of them just like the natural darkness.
The longest reigning tyrant of Gensokyo was Reimu Hakurei, who ruled for a couple of months.
- Reimu Hakurei
- Marisa Kirisame
- Flandre Scarlet
- Jack Frost
- Mama Luigi (formerly)
- Hakurei Shrine -The shrine has become a popular hangout for all sorts of youkai Who Reimu and company defeat. However, because of this, very few (normal) humans come to the shrine, and even fewer (if any at all) leave donations.
- The Scarlet Devil Mansion (紅魔館 Koumakan), also referred to as the Scarlet Manor or Scarlet Mansion, is a European-style mansion owned by Remilia Scarlet. It is located on a ridge on the edge of the Misty Lake. From the outside, there are scarlet-colored windows, but there aren't many windows because of the nature of it's vampires residents . There are plenty of rooms without windows at all, too. There is a clock tower on the roof, but the bell on it only rings at night. The inside of the mansion is much larger than is apparent from the outside. This is due to Sakuya Izayoi's ability to manipulate time and space.
- Human Village - A village where all the Humans live.
- Nameless Hill (無名の丘 Mumei no Oka) is a meadow full of purple and white lilies-of-the-valley on a mountain opposite Youkai Mountain. In the past, it was used as a place to abandon children who then later either died from the poison of the lilies. It is somehow hidden away from the Human Village.
- Moriya Shrine - Another dominant power in Gensokyo, inhabited by gods of
evilsky and earth.
- The Myouren Temple - There are many youkai at the temple training as monks under Byakuren in Buddhism. However, they are still inexperienced and undisciplined.
- Youkai Mountain (妖怪の山 Youkai no Yama) is Gensokyo's largest mountain and volcano. As its name implies, it is inhabited almost exclusively by youkai, primarily kappa and tengu, and where humans are generally not welcome.
- The Forest of Magic - A terrifying forest full of clowns, ghouls, Google employees, pokemon and witches. Unknown and Ryder like to sell goods, from Wander's hat.
- The Bamboo Forest of the Lost (迷いの竹林 Mayoi no Chikurin) is said to be located in the opposite direction to the Youkai Mountain when looking out from the Human Village. Legend has it that the forest was not originally a part of Gensokyo, but was washed over to Gensokyo by a big tsunami. Long long ago, the forest was known as "Tall-Grass Commandery" (高草郡 Takakusa Goori). Inside of it lies the mansion Eientei.
Given the nature of the forest, it is very easy to get lost. There are no clearings, the ground is mostly flat & indistinguishable, and the bamboos grow quickly resulting in a constant change of scenery.
Fujiwara no Mokou lives here assisting any people who get lost, while Tewi Inaba and other rabbits can be seen wandering in the forest.
- Eientei (永遠亭 lit. "House of Eternity") is the name of a large, old-fashioned Japanese mansion hidden deep within the Bamboo Forest of the Lost. It has hallways that lead out into the far reaches of the sky. It was created by Eirin Yagokoro for Kaguya Houraisan.
- The Garden of the Sun (太陽の畑 Taiyō no Hata) is a field full of sunflowers that is home to numerous fairies and youkai, including Yuuka Kazami.
- Ancient city - an underground city full of demons and Magikarp
- The Palace of the Earth Spirits (地霊殿 chireiden) is a mansion situated in the center of what used to be Hell (now Former Hell) in the Underworld, and is near the Former Capital.
- Former Hell (旧地獄 kyuu-jigoku) is a region in the Underworld that was inhabited by many souls long ago that once used to be Hell itself, hence the name. The region itself formed by the bridge guarded by Parsee Mizuhashi at the Deep Road to Hell, the Former Capital of Hell, and the Palace of the Earth Spirits.
- The Netherworld (冥界 Meikai, lit. Gloomy World) is the land where ghosts and phantoms reside after death. After a phantom has been judged by the Yama, they'll either go to Hell, Heaven or here in the Netherworld.
- The Nuclear Furnace (核融合炉 Kakuyuugouro) is a super-high furnace that's used for high-temperature heating, in an attempt to tame a power that the Outside World apparently won't master for hundreds of years: nuclear fusion energy. It is located at the deepest layer of the Underworld, just below the Remains of Blazing Hell.
- Squadala Embassy - The Squadala Empire is the only nation with an embassy in Gensokyo. It exists soley for the purpose of distributing Squadala Man's Shames.
- Higan - a place where the dead are judged.