Palynological and lithofacies analysis was carried-out on dark grey shales and dark sandy clay units from Idah well-1, Northern Anambra Basin, Nigeria. Less attention has been given to hydrocarbon exploration in northern Anambra, hence this necessitated this research. The study aimed at investigating the palynological and lithofacies of study rock types in the study well sections of the basin for paleoenvironmental, paleoclimate, paleoecology and hydrocarbon potential. The palynological analysis of nine shale samples yielded a diverse range of spores, pollens, and marine dinoflagellates indicative of a dynamic depositional environment from the late Cretaceous period. Key diagnostic species recovered include Echitriporites trianguliformis, Stephanocolporite zonorate, Monoporites annulatus, and Cyathidites minor. The depositional environment ranged from marginal marine settings to coastal plains, mangrove swamps, freshwater swamps, and river channels, with indications of periodic marine influences. The paleoclimate analysis revealed a predominantly warm and humid climate with seasonal variations. The paleoecological analysis highlighted diverse ecosystems, including rainforests, coastal plains, mangroves, and freshwater swamps, reflecting a highly dynamic paleoclimate. The lithological analysis reveals a sequence of dark grey shales interbedded by shaley sands and little sandstones thickness, indicative of favourable conditions for organic matter accumulation. The abundance of palynomorph and the detailed lithological and paleoenvironmental analyses further suggest favorable conditions for organic matter preservation and potential hydrocarbon generation.