when did mt rainier last erupt

Mount Rainier last erupted about 1,000 years ago, with the most recent eruption cycle ending around that time. There is some historical report of volcanic activity as late as the 19th century (1820 to 1894), but these are likely to have been dust clouds from rockfalls or cloud caps rather than true eruptions. The Smithsonian Institution and various geological sources commonly cite the last significant eruptive activity at around 1,000 years ago, with some studies indicating the last magmatic eruptions roughly in that time frame as well. No major eruption has been recorded in recent centuries, but the volcano is closely monitored because it is still considered active and potentially dangerous.