Introduction: One of the global strategies for the elimination of schistosomiasis is by Mass Drug Administration (MDA) of a single oral dose of praziquantel (40 mg/kg) without a prior individual diagnosis, with a target of >75% treatment coverage among school-aged children. This study was conducted to determine the endemicity of schistosomiasis among school-aged children and adults in Abuja, Nigeria. Methods: A total of 1370 participants were recruited, which consisted of 667 (48.67%) males and 703 (51.31%) females. Urine and stool specimens were collected from each participant and analyzed using standard procedures. Results: The overall prevalence of schistosomiasis was 27.5% in this study with Abuja Municipal having the highest prevalence of 49%, while the least (6.1%) was reported in Bwari LAC. The prevalence of schistosomiasis significantly differs (p < 0.05) between the area councils. The location of communities significantly affected the prevalence of schistosomiasis in Abaji, AMAC, and Gwagwalada LACs (p < 0.005). The Schistosoma recovered in this study were S. haematobium and S. mansoni. The prevalence of schistosomiasis increased from the baseline of 21.1% to 49% in Gwagwalada LAC. Gender significantly affected the prevalence of schistosomiasis as more males were infected (33.1%) than their female counterparts (22.2%) (p < 0.05). The prevalence of schistosomiasis was 31% and 23.9% among SAC and adults, respectively. The participants’ activities in the river significantly affected the prevalence of schistosomiasis in this study (p < 0.05). Conclusions: The clamour for urgent government and non-government intervention through alternate sources of water like boreholes or pipe-borne water, as well as implementing a behavioural change campaign across the communities to prevent the recurrence, are advocated.