This study aimed to reconstruct social networks in Log Coffin culture, Pang Mapha district, Mae Hong Son Province during 2,120-1,250 B.P. A total of 204 log coffins from 33 archaeological sites were analyzed using Social Network Analysis combined with the carbon-14 ages of log coffins. The results of this study revealed that the networks of coffin head types 1A, 1B, and 5D had the highest density. Types 2A, 2B, 5C, 6C, and 8D were parts of medium density networks. Types 5F, 6A, and 6F belonged to the lowest density networks. Thus, the density of a network is related to how long the types were made and used. Coffin head types with densely connected networks were made and used continuously for a long time, while the coffin head types with small networks were made and used for a short period. The results also showed that Lang, Mae Lana, and Khong sub-watersheds probably were the same cultural group because of the connections between these locales. Additionally, Archaeological sites with high degree centrality scores were locations in which a large number of coffins with various head styles and modified teeth were manifested. This indicates the relationships between different social groups. Further, Carbon-14 dates of log coffins and continuity and variation of coffin head styles demonstrated the dynamic nature of these networks. Finally, the results showed that in 1,700 B.P., interaction between different social groups and the expansion of networks occurred in highland Pang Mapha, evidenced by the distinctive head styles that were presented in this period.