Shortly after the era of the flood, sites associated with a culture called Erlitou began to emerge. To archaeologists, they signal the start of China's Bronze Age: The communities are 10 times as big as the ones that existed previously, and their technology is much more sophisticated. So far, no evidence has been found to definitively link the Erlitou to the mythical Xia. But if the Xia dynasty really did exist, it's thought that the Erlitou sites would have been the lands they ruled.
Source: wiktionary