The post office in Jesselton probably started in September 1900 when the District Office was moved from Gantian. Almost certainly, the company flag was raised on the subsequent New Year 's Day. Gantian was founded in June 1898 after the sacking of Gaya by Mat Salleh in 1897.
Unfortunately, it was a very bad choice with an unsettled harbour. It was also isolated from the mainland by mangrove swamps. But we had a post office and a rare postmark for a large part of 1900 before Gantian was abandoned in favour of Jesselton nearby to the south.
The Gayah post office continued until the end of 1899. Was it possible that Gantian made use of the Gaya canceller in this transitional period? I think this Gantian of old was located fairly near to the the present day Universiti Malaysia Sabah (UMS) campus but do correct me if I am wrong.
This is a fairly early Jesselton D2 cds of 6 MAR 01. Where is D1? Did Proud expect it to be discovered sometime?