Recent fieldwork by the Industries of Angkor Project (INDAP) has identified the first extensive evidence of iron production within an Angkorian Khmer (9th to 15th centuries AD) center at Preah Khan of Kompong Svay (Preah Khan) in Preah Vihear province, Cambodia. This immense 22-km2 temple complex appears to be an outpost of Khmer settlement situated in close proximity to Phnom Dek (“Iron Mountain”), the richest known source of iron oxide in Cambodia. Combined with the fact that Preah Khan's temple architecture dates between the late 10th to early 13th centuries, the period that the Khmer greatly expanded their territorial influence, our primary hypothesis is that this complex was established to gain access to and monitor production of iron for the capital of Angkor. The vast number and size of these iron slag concentrations, some up to 5 m in height by 35 m in length, precludes the use of traditional excavation and dating methods. Instead, this paper employs 14C dating of “in-slag” charcoal from surface slag cakes to produce a spatial chronology of late or “terminal” industrial activities. The results indicate that metallurgy was “last” practiced at various locations within Preah Khan in the mid-13th to late 17th centuries, with 3 distinct clusters between the late 13th and late 15th centuries. Based on this initial survey of surface collections, it appears that iron production at Preah Khan occurred after the final phase of masonry construction. More significantly, this work provides the first robust set of dates for late Angkorian and Middle period industrial activities in Cambodia.