East District is the east part of Mount Paozu, the west part being Diablo Desert. It is the area on Earth where Grandpa Gohan was settled and where Goku would consequently inhabit during his days as an orphan and his life in adulthood. It is also the location of Vodka's fortress.
Being situated in the heart of Mount Paozu, East District appears to be surrounded by lush greenery and beautiful fields, as well as being heavily populated by the strangest of Earth's creatures and lifeforms. The location itself is actually seen multiple times throughout Dragon Ball. The East District is first physically seen in early Dragon Ball, during the start of the Emperor Pilaf Saga, and is later officially named in Dragon Ball Z when the Androids are hunting for Goku, as Android 16 divulges to the other pair of cyborgs the exact location of Goku's whereabouts as "439 East District".
In the Majin Buu Saga, the East District is partially referenced by Gohan when referring to his address to his classmates, as well as serving as a training ground of sorts for Goten during his sparring sessions with Chi-Chi. The eastern forest here also served as training ground for Gohan and Goten during their preparation for the 25th World Martial Arts Tournament.
In the Dragon Ball GT special, A Hero's Legacy, Goku Jr. would eventually travel through the district in an attempt to resurrect his grandmother and Puck, both of whom he would presumed dead. There, he meets the demons Mamba, Susha, Torga, and Lord Yao.
In Dragon Ball Z: Attack of the Saiyans, this area is called East Mt. Paozu and enemies encountered in here are Wolf, Thug, Female Bandit, Violent Tribesman, Rabbit Survivor, and Vampire Bat. Yamcha was training in the river between the desert and East Mt. Paozu right before the arrival of the Saiyans on Earth.
In Dragon Ball Z: The Legacy of Goku II, East District is also the location of Vodka's fortress as well as the Four-Star Dragon Ball during the Cell Games Saga. Enemies encountered in the East District's forest are wolves and snakes, and Vodka's fortress is protected by a Ninja Clan, a Mercenary Clan, ladybugs, Eggbots, a Green Destroyer, and Cyborg Tao. Squirrels are also shown to live in the forest.
In Dragon Ball Z: Buu's Fury, Gohan and Goten spar a bit here, like in the anime/manga.