This article employs the research paradigm of historical ecology to investigate the spread and development of early Buddhism in the Khorat Plateau during the Dvaravati period. The movement of this religion into the region was largely determined by preexisting settlement patterns, with moated sites being particularly important. The arrival of Buddhism also introduced monumental architecture and a definable art style. These moated settlements were dependent on large-scale river systems such as the Mun and Chi, particularly in regard to water management, agriculture, transport, and communication. A study of the distribution of sema stones also provides evidence for the spread of Buddhism, while Buddha images carved into rock faces on mountaintops and evidence for rock shelters illustrate that the tradition of forest monks was functioning alongside the more established urban monasticism. The relationship between Buddhism and society is explored, illustrating how the arrival of this religion resulted in new cognitive and physical conceptions of the landscape best demonstrated by changes in settlement planning. Finally, it is shown that Buddhism did not function outside of society but existed in an interdependent relationship with both the lay community and local rulers, with patronage being granted in return for not only spiritual guidance but political legitimization.