The outer wall is a crescent shaped earthen rampart enveloping the inner wall and moat. The outer wall starts near Chaeng Sri Phum (Propitious Conner) at the northeastern point of the inner city. It runs along Nam Mae Kha (Mae Kha canal). Then westward to link up with the inner wall at Chaeng Ku Hueng at the southwest conner of the inner city

 Five gates that used to exist in the outer wall were Chang Moi, Ta pae, Lai Khaeng, Kue Kom and Hai Ya.

Evidences show that the outer wall was built later than the inner wall to strengthen the city defence on the south the remains of a fortress of 11 metres high and an earthen rampart of 8 metres high can still be seen