Termina is a duplicate of Hyrule, which is assumed to exist in an alternate universe. As such, it contains many of the same locales and inhabitants, which more or less may have the same purpose or occupations. Termina was presumed to be created by the Four Giants which reside in the four compass directions.
At the time Link arrives, Termina is overlooked by a menacing Moon, pulled down from its orbit by the Skull Kid, using the power of Majora's Mask. The malevolent satellite grows closer with each passing day, and will inevitably crash directly into Clock Town, ending all life in Termina, shortly after midnight on the third day. The only ones in the land who could possibly stop it, The Four Giants, have been magically sealed away by the bitter Skull Kid.
Termina is scarcely populated during this time. It is an ever-growing conflict between the various citizens if they should evacuate Clock Town and move into surrounding areas in the hope of surviving the Moonfall, or whether they should remain and hold the annual Carnival of Time as planned. Many have already left, and some don't believe the moon will really fall at all. Others have grimly realized the truth: running is futile, because the falling moon will bring about the end of the entire world.
Five major regions exist in Termina, residing in the four compass directions, with Clock Town in the center.
The Center of Terminan life and activity, the majority of Termina's inhabitants once lived here. It is where the Carnival of Time is held annually to celebrate the Goddess of Time and the Four Giants. Its major landmark is a giant clock tower which can be seen from all over the land, and which turns into a platform for celebration every year on midnight of the first day of the festival.Clock town is surrounded by Termina Field, which serves as a hub for reaching the other regions.
A marshy area that exists south of Clock Town. Home to the Deku Palace and the royal Deku family, the area has become poisoned and foul because of the toxic water emanating from Woodfall Temple.
An icy region to the north, and home to the Gorons. The Skull Kid has locked the area into perpetual winter through a magic seal located somewhere inside Snowhead Temple, and the coming of spring has been delayed indefinitely. After defeating the boss at the end of Snowhead Temple spring arrives and most of the snow around the mountain melts. This allows access to new areas such as the Goron races.
Great Bay is a large shoreline to the west which is home to the Zoras and the all-female Gerudo pirates. A large storm has made reaching the off-shore temple all but impossible. Even after Great Bay Temple is purged of its evil, swimming out to sea is impossible due to the intense murkiness of the water. (or, more accurately, to keep the area a reasonable size so the Nintendo 64 processor can render it)
Home to the once-great but now extinct Ikana Kingdom, Ikana Canyon, north of Clock Town, is ravaged by death and drought. The ruins of Ikana Castle, home to their last great king, Igos du Ikana, still remain standing. The river has dried up, and Gibdos now plague the area, and the graveyard is haunted. One single family still lives here, inside a house containing a huge music box that plays a song that inexplicably drives Gibdos away. Unfortunately, it is powered by a water wheel, and with the river dried up, the family currently huddles in fear inside the house, while the hungry Gibdos circle it endlessly.