In the late prehistoric and early historic periods (2,120–1,250 B.P.) in highland Pang Mapha, northwestern Thailand, the Log Coffin Culture represented a unique mortuary practice characterized by specific cemetery locations and coffin stylistic variations within a localized region of mainland Southeast Asia. Highland peoples practiced these mortuary patterns for an extended period, indicating that specialized cultural practices were passed between successive generations. This article examines the communities of practice of coffin production to understand how this knowledge transmission occurred over roughly 1,000 years. We conducted a quantitative analysis of 202 coffin heads from four river drainages. Similarities of coffin head proportion and carving techniques suggest that highland peoples shared techniques among craft communities in sub-regional watersheds, including the Lang, Mae Lana and Khong rivers, for generations. The difference in head proportion and surface treatment also suggests that producers conceivably adopted some aspects of traditional techniques and developed individual styles.