The Richardson Mountains (RM) of northwestern Canada form a tectonically active boundary between the northern Canadian Cordillera and stable North American craton. Although host to abundant seismicity, the RM modern geometry and kinematics remain poorly resolved. To better delineate active structures, we apply double-difference (DD) earthquake relocation to all seismicity in the Canadian National Earthquake Database (NEDB) between 2015 and 2021 (775 events). We jointly invert catalog P and S-wave picks and waveform cross-correlation measurements with the scrtdd implementation of HypoDD. The resulting 594-event catalogue reveals two zones. Along the eastern front of the central RM, DD relocations collapse into a sharply defined west-dipping plane extending from the surface to 35 km. Its approximate 75° dip and surface intersection with the Knorr fault suggest that contemporary deformation is reactivating a Paleozoic normal fault. In contrast, seismicity remains broadly distributed across the White Mountains and Barn uplifts, reflecting deformation partitioned among several interacting inherited structures within a complex deformation zone. A reduction in seismicity between these regions (in both original and relocated catalogues) may indicate structural segmentation or a locked segment with implications for seismic hazard. These results demonstrate the effectiveness of DD relocation for resolving active tectonic structures in remote northern regions and provide a refined framework for future investigations. Continued incorporation of new data from the Western Arctic Regional Network of Seismographs (WARNS) will support improved assessments of crustal deformation and seismic hazard in Canada’s North.