Mount Rainier’s most recent confirmed volcanic eruption was about 1,000 years ago, with the last recognized eruptive period ending roughly around 1000 CE. Historical reports describe small steam or ash events in the late 1800s (often cited as 1894–1895), but these are minor and not all are clearly confirmed by deposits.

Mount Rainier is therefore considered an active volcano that is currently “at rest between eruptions,” and it continues to be closely monitored for future activity.

Information gathered from public forums or data available on the internet and portrayed here.