Boundary Street is a three-lane one-way street in Kowloon, Hong Kong. It runs in the eastbound direction starting at its intersection with Tung Chau Street in the west, and ending at its intersection with Prince Edward Road West in the east, near the former Kai Tak Airport.
Historically, the street marked the boundary between the southern part of Kowloon, ceded by Qing China to the United Kingdom in 1860, and the northern part of Kowloon (New Kowloon), which remained part of China until it was leasedas part of the New Territories to the United Kingdom in 1898 for 99 years. After the lease, the boundary was renamed from Boundary Line to Old Frontier Line.
The boundary was made visible by a long line of high bamboofences which effectively blocked smuggling between Chinese Kowloon and British Kowloon at that time. It became obsolete when New Territories joined the colony.
Although the street is the historical mark on the boundary, the road did not come to exist until 1934, more than 30 years after the lease of boundary north. The road was built to accelerate the development of Kowloon Tong and identify the difference in calculation of rates between the boundary north and south.