Iron was a major contributor to the success and expansion(s) of the Angkorian Khmer Empire (11th to 13th centuries CE). The Industries of Angkor Project has focused on this process through a combination of regional survey, intensive site excavation and multidisciplinary analysis. Tonle Bak, is situated just south of the Phnom Dek, or Iron Mountain metallurgy sites. Recent work at the Tonle Bak site uncovered the first evidence of Angkorian era furnace structures, smelting organization and formation processes of the large slag concentrations found across the Phnom Dek industrial landscape. More importantly, discovery of a diverse ceramic assemblage, economic plants, and the remains of a wooden religious structure indicate that Tonle Bak was home to a sedentary community who actively smelted iron and interacted with the broader Angkorian economic network. The nature of the assemblage raises further questions about the isolation of primary smelting sites in general, and which group(s) may have been responsible for manufacturing iron during this important period in Cambodia’s past.