This study addresses the lack of chronometric research on the common bean (Phaseolus vulgaris L.) to establish precisely the timing of its adoption and spread across the northern Eastern Woodlands of North America. Bean and directly associated maize samples were subjected to accelerator mass spectrometry (AMS) dating. The results show that the common bean apparently spread rapidly upon its introduction to the region, becoming archaeologically visible from the Illinois River valley to southern New England in the calibrated late 13th century AD, some 200–300 years later than previously thought.