While the Kowloon in the game is fictional, it is based on the Kowloon Walled City (Japanese: 九龍城 Kyūryū-jō or 九龍城砦 Kyūryū-jōsai) located on mainland China, before its demolition in 1993. Despite being on the mainland of China, Kowloon is an enclave of Hong Kong, so still part of the Hong Kong territory. The game depicts Kowloon with some artistic liberties, such as being on a hill, further away from the nearby city, etc.
The city is filled with many high rise buildings, the largest being the Yellow Head Building.
These are the areas Ryo can visit in Kowloon.