Neoarchean terranes formed during one of the principal phases of crustal growth in Earth history and host some of the world’s most significant mineral resources. Understanding the lithospheric architecture and tectono-magmatic evolution of Neoarchean terranes is therefore fundamental for understanding their potential mineral endowment. Archean rocks in the northeast Democratic Republic of Congo (DRC) underlie ~80,000km2 of the Congo Craton, and are one of the least studied Archean terranes in the world. Here we report 74 LA-ICPMS Lu-Hf and 49 SHRIMP oxygen isotope determinations on zircon from 69 granitoid and 5 siliciclastic sedimentary rocks from the NE DRC. These data form part of the first regional-scale study of the geochronology and isotopic character of Archean rocks in the NE DRC. Felsic-intermediate magmatism across the NE DRC occurred between c.3200 and 2530 Ma with the principal episode of plutonism and crustal growth occurring between c.2670 and 2530 Ma. This plutonism included three geochemically distinct suites; an earlier (1) sodic-calcic suite with high Sr/Y ratios, and a broadly coeval (2) calc-alkaline to high-K suite with low Sr/Y ratios emplaced between c.2670 and 2600 Ma, and (3) a largely younger ferroan, high-K calc-alkaline suite with elevated HFSE that were mostly emplaced between c.2600 and 2550 Ma. A minor but distinct shift in zircon O-Hf isotopic values is observed between these two broad episodes of magmatism, with the two earlier magmatic suites characterised by more “mantle-like” isotopic values (δ18O = +4.5‰ to +7.0‰; εHf(t) = 0 to +4), and the younger HFSE-elevated suite characterised by “crustal” evolved values (range of δ18O = +5.0‰ to +7.7‰; εHf(t) = -1 to +2). This isotopic shift at c.2600 Ma may reflect a minor increased contribution from recycled older supracrustal material. Alternatively, it could reflect input of hot, enriched asthenospheric mantle coupled with closed system fractionation that would also result in granitoids with these Hf and O isotopic characteristics. The ferroan, HFSE-elevated chemistry and lack of inherited zircon in the younger suite supports the latter interpretation. Distribution maps of the Lu-Hf isotopic data highlight a clear isotopic boundary in the eastern part of the northeast DRC that coincides with the contact between Neoarchean plutons and the composite West Nile Gneiss which includes Mesoarchean granitoids emplaced as early as c. 3200 Ma. Zircon from the West Nile Gneiss have strongly negative εHf(t) values (range -8.6 to +2.0) which contrast with those of the more primitive Neoarchean plutons to the west. The range of U-Pb ages (3.2 – 2.6 Ga) and strongly evolved isotopic composition of granitoids from the West Nile Gneiss suggest that it is underlain by an ancient Meso- Paleoarchean lithosphere, some of which may have been in place as early as c. 3.8-4.0 Ga whereas lithosphere under the rest of the northeast DRC is Neoarchean in age. The boundary between the West Nile Gneiss and the Neoarchean granitoid terrane to the west is therefore likely a major trans-lithospheric structure whose scale and isotopic character are comparable with similar boundaries in the Archean Yilgarn and Superior cratons.