From Bulbapedia, the community-driven Pokémon encyclopedia.
HopHopHop Town (Japanese: ヨヨヨタウン YoYoYo Town) is a location that only exists in the Pokémon anime. It is a close suburb of Celadon City.
Bearing a closer resemblance to a city, the urban town is made up mostly of large buildings and sky scrapers. In the episode it is featured in it is shown to have a large Pokémon Center. Despite the lack of greenery around the streets, a blooming garden is located on top of one of the enormous skyscrapers inhabited by a Drowzee and Hypno. A very similar garden would later appear in Curbing the Crimson Tide, although no references were made to link the two areas.
HopHopHop Town was featured in the episode Hypno's Naptime. Ash and his friends learned that several children had gone missing in the city, and several Pokémon were suffering from fatigue. With the help of Officer Jenny, they were able to discover the source of the problem; a group of people suffering from insomnia were using a Hypno to help them fall asleep. After Misty was hypnotized by it, she ran into a park thinking she was a Seel, where all the missing children were discovered, thinking they were Pokémon. Using Drowzee, the children were cured and sent home to their parents.
HopHopHop Town is home to the Pokémon Lover's Club. Members reportedly all suffer from the sleep condition, insomnia, but through the use of a Pokémon, they overcame their symptoms.
In addition, HopHopHop Town is where Misty captured her Psyduck. Brock promised Nurse Joy he would take care of it, but changed his mind after seeing it. Psyduck captured itself inside of one of Misty's Poké Balls, making it hers.
Pokémon seen in HopHopHop Town