Surrounded by limestone hills, on the bank of the Kwae Noi, is the ancient city of Muang Sign, located in Tampon Sign (or Lion Sub-district) of Amphoe Sai Yok (or Sai Yok District). It is about 45 kilometres from Kanchanaburi and 175 kilometres from Bangkok. The ancient city of Muang Sign is almost square-shaped, surrounded by moats, ramparts and laterite city walls.

The laterite wall around the city is 880 meters long, with gates on all four sides. The city area is about 641 rai 1 ngan and 65 tarangwa (6.25 rai = 1 hectare).

The south wide of the wall winds along the Kwae Noi river, there is an embankment of earth on each of the other inner sides of the wall, the outer sides are enclosed with seven moats and ramparts. These moats and ramparts were probably constructed for the water control system as well as for fortification.

There are also six ponds in the ancient city which were possibly used for religious and irrigation purposes.