Saphan Pa Than or the “Bridge of the Charcoal Market” is located on the city island in Pratu Chai Sub-district, on the edge with Tambon Tha Wasukri. The structure can be found on the crossing of Naresuan Rd (former Pa Than Rd or also Chao Phrom Rd) and the Chikun Rd opposite Wat Racha Burana.
The brick bridge was built over Khlong Pratu Khao Pluak (also called Khlong Pratu Jin in the southern stretch) which connected the old Lopburi River (later Khlong Mueang or City Canal) in the north (near Wat Tha Sai) with the Chao Phraya River in the south at Pratu Jin. This canal was filled in last century and as thus at present inexistent, with the exception of a small stretch of water between Wat Tha Sai and Wat Racha Praditsathan - close to its former mouth, called Pratu Khao Pluak. Only some brick work of the former bridges remain as a last witness of the past.
The location was once a princely battleground. It was here that the two elder sons of King Intharacha (r.1409-1424), Ay Phraya and Yi Phraya fought for the throne of Ayutthaya in 1424. Both were severely wounded and died from the combat. The youngest brother, Chao Sam Phraya was then proclaimed King. He ordered two chedis built on the site where his brothers engaged in combat and these still can be seen west of the bridge.
Yan (area) Pa Than was a morning and evening fresh market selling various kinds of fruit such as oranges, bananas, sugarcane and other fresh food. The market was formed with stalls, some permanent, or mats on the ground and was only functional in the morning and evening. There were about 40 of these markets within and without the city walls. 
The foundations of the Pa Than Bridge (likely over-renovated) are still visible. The brick bridge in European style can be taken as a model for all the other bridges in the city. It was an arched construction with three sharply curved bows, the middle one higher and wider than the two others, making it possible for boats to pass underneath. The construction dates likely from King Narai’s reign (r. 1656-1688). Pa Than bridge stood at a road crossing of two brick roads; one running north-south along the Khlong Pratu Khao Pluak - Pratu Jin, the other one running east-west towards the Chao Phrom market.