Pom Thung Setthi is an old laterite fort in Kamphaeng Phet, situated on the west side of the Ping river and which dates roughly from the early 16th to mid 17th century AD.

It  was reportedly built by the Portuguese, who not only were hired as mercenaries and to train the Siamese, but since 1518 AD already supplied Siam with guns and ammunition.

The fortress is built as an European style star fort, a bastion with a square floor plan and arrow-shaped bulwarks, i.e. angular structures projecting outward from the curtain walls of the fortification.

Those  bulwarks are positioned at each of the four corners, which allowed for fire from the flanks and a offers a better defence of the curtain walls.

The walls are approximately 6 metres high and whereas the distance between the tip of the bulwarks is circa 82 metres, the curtain walls measure around 52 metres and at the base have a thickness of about 3.5 metres. The battlement is topped with a crenellated parapet that consist of merlons called bai sema, which at the base each have a horizontal loophole. At the bottom, the thick inner walls have large, deep bunker-like niches in the form of a house-shaped pentagon, some of which have a single window of the same shape in the outer wall. On all four sides, in the middle of each curtain wall, is a large gate.