India, the timing and geography of human demographic expansions in continental Southeast Asia remains ambiguous. The recent discovery of a series of stone artifacts spread over a basalt level at Ban Don Mun in the Lampang province of northern Thailand presents an ideal opportunity for reevaluating lithic assemblages documented during the 1970s and 1980s in the same region. Both the position of these stone tools and new absolute dates indicate a Middle Pleistocene age and call into question the status of these artifacts as the oldest yet found in Southeast Asia. The uncertain geo-chronological context and technological analysis of the chopper industry from previous work in the Lampang area prompted us to undertake new surveys in continental Southeast Asia in order to help clarify the route and timing of Pleistocene human expansions in this part of the world.