Archaeological evidence suggests that between about 500 BC and 200 AD, a rice-growing population was living in a densely settled system of small villages in the Samon Valley in Upper Myanmar. This area was at the crossroads of ancient trade routes. Wealth was accumulating due to agriculture and to access to the copper resources of the Shan hills, the semi-precious stone and iron resources of the Mount Popa plateau, and the salt resources of Halin. This wealth is evident in grave goods unique to the Samon region, which includes items traded from or inspired by Qin and Han Dynasty China. This paper will explore the possibility that the appearance early in the First Millennium AD of the walled Pyu cities of Maingmaw, Beikthano, Halin and Sriksetra, at remarkably consistent distances from the Samon Valley, may be a consequence of intra-regional population flow from the Samon area. While the Pyu cities shared cultural elements such as religious and decorative items, and coins bearing auspicious symbols, with neighbours including Dhanyawadi and Vesali on the west coast, the Dvaravati settlements of Thailand, and trade centres such as Oc Eo in Vietnam, their relationship to the landscape, to each other and to the Samon valley suggests that they formed a distinct economic and cultural system (Gutman & Hudson 2004).