Abstract Archean orogenic lode gold deposits are the result of large, complex mineralizing systems that have developed within many Archean terrains. Mineralizing systems are defined to include all geologic factors that control the generation and preservation of mineral deposits and emphasize the processes responsible for deposit formation at a variety of scales. Deposits belonging to Archean orogenic lode gold mineralizing systems comprise epigenetic mineralization that formed as a result of focused fluid flow late during active deformation and metamorphism of volcano-plutonic terranes. They can occur in any lithology and formed at a range of paleocrustal levels through site-specific and local physical and chemical processes. All Archean orogenic lode gold deposits formed through broadly similar geologic processes, with the unique character of individual deposits resulting mainly from variations at the depositional site. The key feature of Archean orogenic lode gold systems is a broadly uniform low-moderate salinity, mixed aqueous-carbonic fluid that is capable of carrying Au but has limited capacity to transport base metals. Models for development of orogenic lode gold mineralizing systems are generally poorly constrained, although geologic and geochemical characteristics are consistent with terrane- or larger-scale processes. Archean terranes containing orogenic lode gold systems include accretionary and collisional settings. Mineralization is generally late in the tectonic evolution of the host terranes; is typically syn- to postpeak metamorphism, becoming increasingly postpeak at higher paleocrustal levels; and is indicative of clockwise metamorphic P-T paths and implicating processes involving “deeper later”-type metamorphism. There are few robust absolute ages on mineralization although, in most terranes, available ages indicate mineralization follows major volcanic, sedimentary, and plutonic episodes. In many terranes, mineralization is coincident with mid-crustal felsic magmatism. Young absolute ages recorded in some deposits probably reflect resetting and/or new mineral growth during post-gold mineralization hydrothermal activity and/or slow cooling of host terranes. The source(s) of fluids and metals in orogenic lode gold systems is poorly understood; however, mineral equilibria and isotope tracers implicate sources deeper than presently exposed greenstones. Isotope tracers and mineral equilibria are also consistent with derivation from and/or equilibration of the ore fluid with felsic rocks during transport of hydrothermal fluids to depositional sites. Stable and radiogenic isotope tracers alone do not distinguish between fluid derivation through metamorphic devolatilization and magmatic fluid evolution. Some deposits formed at high paleocrustal levels, however, and record the influx of surface waters. Transport of large volumes of broadly uniform hydrothermal fluids over relatively long distances is implicated and requires channelized fluid flow with minor modification of major molecular components en route from source to depositional sites. Selected major deformation zones that are truly “crustal scale,” as demonstrated by deep seismic profiling, provide ideal fluid pathways for deeply sourced hydrothermal fluids. The largest gold provinces show spatial proximity of world-class lode gold deposits to “crustal-scale” deformation zones (e.g., Boulder-Lefroy, Destor-Porcupine). Linking of active faults is important for fluid focusing and effective transport of hydrothermal fluids. The hydrothermal fluids transport gold along the pathways as one or more neutral and reduced sulfide species. Chemical modeling demonstrates that the inferred hydrothermal fluids can effectively transport gold over long distances and over a significant crustal-depth range. Provided the fluids remain effectively channelized during transport to higher crustal levels, camp- and deposit-scale structural focusing and associated local gold precipitation mechanisms are required to ensure development of economic gold mineralization at the trap site. Archean orogenic lode gold mineralizing systems have distinctive depositional site characteristics at both the camp and deposit scale. Camp-scale features include geochemical signatures related to regional alteration surrounding major deformation zones, large-scale structural inhomogeneities (e.g., bends in major deformation zones, district-scale granitoid-greenstone contacts), and the presence or absence of overlying rock successions that can act as barriers (e.g., seals, aquicludes) to fluid movement. Deposit-scale variables include the local host rocks, structural traps (fault intersections, contacts between contrasting lithologies) typically in zones of low mean stress, and the P-T conditions in the host sequence. Resulting alteration assemblages primarily reflect interaction of host lithologies with the hydrothermal fluid at a particular pressure and temperature. Alteration assemblages generally show enrichment in K, CO2 and S in deposits irrespective of paleocrustal level. A metal association of Au, Ag ± As, B, Bi, Sb, Te, and W is displayed by most deposits. Fluid-inclusion-derived data at individual deposits show a range in compositions, although salinity is generally low to moderate, with mixed aqueous-carbonic compositions. Variations in CO2, CH4, N2, salinity, and redox-state may reflect district- to local-scale processes and/or specific host rocks rather than differences in fluid source. Deposition at the trap site is likely to reflect catastrophic effects in response to physical changes (e.g., large pressure fluctuations, seismic events), with resultant chemical changes due to local fluid wall-rock interaction, phase separation, and/or fluid mixing. The extreme diversity of Archean orogenic lode gold deposits reflects the complex interplay of physical and chemical processes at a trap (depositional) site localized at various crustal levels ranging from sub-greenschist to upper-amphibolite facies metamorphic environments, with gold precipitation occurring over a correspondingly wide range of pressures and temperatures. The variability in deposit characteristics largely reflects the P-T conditions, variability in host rock, and local changes in ore fluid composition.