The "Cheung Chau (Residence) Ordinance, 1919", passed on August 28th that year, stated "no person shall reside within that southern portion without the consent of the Governor-in-council.". 

When the law was first proposed in the Legislative Council, the two Chinese members were firmly against it. Mr Ho Fook declared: "In view of the fact that the war has been won by all races in the Empire I cannot be party to the passing of the Bill which, in my opinion, is nothing less than racial legislation. I hope you will see your way to withdraw this Bill as suggested by my colleague."

The British stuck to the line that the law was intended to preserve the southern area as a place where British and American missionaries could live with their families. The missionaries needed a place to rest after spending time working in Southern China. They had previously used the Peak but it had become too expensive so they had turned to Cheung Chau. Now there was the risk that would also become too expensive, so they'd turned to the British government for protection. The law gave the missionaries the protection they needed, and was "an entirely economic question and not a racial question at all." The law was passed that same day.

In July 1946, Bills were introduced to repeal both laws that restricted residence on the Peak on Hong Kong island and in south Cheung Chau. In both cases the Attorney General noted that "it would be out of harmony with the spirit of the times to retain the Ordinance".

There are nine remaining boundary stones: numbers 2, 3, 4, 6, 7, 9, 11, 13, 14. You can find them on the Hidden Hong Kong Map, note however that some are on private property, number 14 being inside St John's Hospital!