The thermal structure of the lithosphere has a first-order control on continental growth and the stabilization of cratons. Metamorphic rocks record pressure (P)–temperature (T)–time (t) information that can provide essential constraints on a wide range of geological processes leading to cratonization, such as changes in the thermal environment over time. The Geological Survey of Western Australia is currently undertaking detailed geoscientific studies across the Yilgarn Craton, including forward modelled phase equilibria calculations integrated with in situ geochronology and thermochronology to constrain P–T–t conditions of metamorphism. These datasets are being used to better understand the protracted evolution of the Yilgarn Craton, but may also be applicable to other Archean terranes worldwide. The metamorphic database currently contains more than 40 data points across the Yilgarn, representing one of the most well characterized quantitative metamorphic datasets worldwide. The data show that granulite and amphibolite facies conditions dominate the southwest Yilgarn, with apparent thermal gradients ranging between 65 and 225 °C/kbar at 2665–2635 Ma. Much of the current dataset is from the northwest-trending Corrigin Tectonic Zone (CTZ), a major sinistral transpressive shear zone system comprising granulite-grade, mid-crustal meta-igneous and metasedimentary rocks. East of the CTZ, within the southern Youanmi Terrane, the data suggests that P–T conditions are broadly similar to the conditions recorded in the CTZ. West of the CTZ, within the South West Terrane, there is a scarcity of exposed metamorphic rocks, but field observations are suggestive of a lower metamorphic grade. Elevated apparent thermal gradients seem to correspond to elevated crustal radiogenic heat production. The crustal evolution of the southwest Yilgarn is characterized by voluminous granite magmatism between 3010 and 2610 Ma. A compilation of all inferred Archean rock types sampled in the southwest Yilgarn shows that the crustal rocks are elevated in radiogenic heat production with an average value in the dataset of 7.1 µWm-3 (n=1260) at 2640 Ma, compared to the global crustal average of 2.78 µWm-3 (calculated at 2640 Ma). A long history of elevated heat production in the crust is implied by the calculated heat production of granitic rocks that make up a significant portion of the southwest Yilgarn crust, which were emplaced prior to, synchronous with, and following the 2665–2635 Ma metamorphism. In addition, amphibolite to granulite facies supracrustal rocks in the southwest Yilgarn have elevated radiogenic heat production values (on average 3.3 µWm-3, n=27). Together these imply that at the time of 2665–2635 Ma high-T metamorphism, and at the depth where amphibolite to granulite facies metamorphism was occurring, the crust was also strongly enriched in heat-producing elements, and that contemporaneous magmatism was sourced from crust with elevated radiogenic heat production. The thermal structure of the crust during Neoarchean metamorphism was likely a combination of elevated crustal heat production, the effects of regional-scale granite magmatism, and a juvenile mantle contribution at depth.