The oldest iron (maybe bronze, forgot which) making site in the world is located in Thailand. That suprised me.
Huh, interesting. I hadn't heard that before, so I just looked it up. I guess the site is named Ban Chiang:
Bang Chiang is an archeological site located in the Udon Thani province, Thailand. It is listed in the UNESCO world heritage list.
Discovered in 1957 it attracted enormous publicity due to attractive red painted pottery. The first scientific excavation was made in 1967 and uncovered several skeletons together with bronze grave gifts. Rice fragments have also been found, which prove that the bronze age settlement was made by farmers. The oldest graves found contain no bronze and are therefore from a neolithic culture; the latest ones are from the iron age.
The first datings of the artefacts using the thermoluminescence technique resulted in 4420 BC-3400 BC, which would have made the site the earliest ever bronze age culture of the world. However with the 1974/75 excavation enough material for radiocarbon dating became available, which resulted in much later dates - the earliest grave was at about 2100 BC, the latest of 1320 BC-1000 BC.
References
Charles Higham, Prehistoric Thailand, ISBN 9748225305 , pp 84-88