The 1872 North Cascades earthquake occurred at 5:40 a.m. local time in northern Washington state on December 15. A maximum Mercalli Intensity of VIII (Severe) was assessed for several locations, though less intense shaking was observed at many other locations in Washington, Oregon, and British Columbia. Some of these intermediate outlying areas reported V (Moderate) to VII (Very Strong) shaking, but intensities as high as IV (Light) were reported as far distant as Idaho and Montana.