Travancore (now part of Kerala, Southwest India) was one of the states under the Madras Agency, which was a system established under the British colonization of India. While the Madras Agency was established in 1923, the kingdom of Travancore dates back to 1729. The post office dates back to 1784 and, before the British post office was established around 1860 for private letters, was used only by government officials.

Before 1888, regular revenue stamps of India overprinted "Travancore" were used in the state.

Revenue stamp issued in 1887 used in the state 

The first stamps of Travancore, issued October 16, 1888

These first stamps were printed in sheets of 56, 60,70, and 84 stamps. Stamps that were issued in later years were printed in sheets of 112 and 168 stamps. The perforations on these first stamps measured 12 or 12.5. Stamps that were issued later also included perforations of 11 and 13.5. Some varieties and errors of the later issues also include double surcharge, inverted surcharge, and imperforate pairs of the stamps. The center is also shifted on some later issues, and a lot of errors and varieties are still unlisted. 

A watermark did not appear on Travancore stamps until 1890, and it is the only watermark that ever appears on stamps from the state. There are various varieties such as the watermark being sideways, inverted, shifted or omitted entirely from the stamp or from part of the stamp (which was found often).  

In 1949, Travancore became a part of Cochin, which was a neighboring (and rival) state. All stamps issued by Travancore were able to be used on postage until 1951.