So if you think that the lakes in the area have been around for a while (they’re roughly 12,000 years old or so, they are mere babes when compared to the Mount Rainier. “The Mountain” as it’s called by some in the area had its start some 840,000 years ago, when its earliest lava flows can be determined. It took 340,000 for those lava flows to form the cone found serves as the foundation for the volcano/mountain we know and love today.

Mt. Rainier is an active stratovolcano, which is a formal way of saying it’s a conical volcano with periodic eruptions from time to time. If you made a volcano for your science fair, chances are you made a model of a stratovolcano. . Other well-known stratovolcanoes include Krakatoa and Vesuvius. For residents, that can be a terrifying observation if they were to give it any in depth thought. However, because Mt. Rainer can currently be considered “at rest”, it’s easy for the locals to ignore the sleeping giant south of Seattle. It’s important to note that “At rest” is just another way of saying that the volcano is currently between eruptions, with the implications of that sentence being intentional. Mt. Rainier will erupt again, someday.

The last noted activity of Mt. Rainier was in December 1894, when local newspapers reported black smoke rising from the mountain’s summit. But whatever activity had occurred on the mountain was minor in nature, and no lava flow was detected. The last lava flow eruption of Mt. Rainier likely occurred 2200 years ago. It’s easy to ignore the threat of Mt. Rainier when it hasn’t been destructive since the heyday of the Roman republic.

The Mountain top most peak has an elevation of 14,417 ft. Geologists believe the mountain was once 16,000 feet but due to mudflows, glaciations and avalanches, its elevation decreased over time. Mount Rainier has 26 major glaciers, and has 35 square miles of permanent snow fields and glaciers. It is the United States' most glaciated mountain.

Mount Rainier's river valleys, forests and meadows were once inhabited by various Native American tribes, long before those of European descent had shown up. . The local tribes included the Muckleshoots, Puyallups, Yakamas, Cowlitz's, and the Nisqually. They referred to the mountain as Tacoma, Talol, Tahoma, Tacobeh, and Pooskaus, depending upon the tribe and era.

George Vancouver gave the volcano the name Mount Rainier in 1792, in honor of his friend Rear Admiral Peter Rainier. In his journal of his trip to the Pacific Northwest, he states:

"The weather was serene and pleasant, and the country continued to exhibit between us and the eastern snowy range the same luxuriant appearance. At is northern extremity, Mount Baker bore by compass N. 22E.; the round snowy mountain, now forming its southern extremity, and which, after my friend, Rear Admiral Rainier, I distinguish by the name of Mount Rainier, bore N(S) 42 E."

The news got around fairly quickly, as Lewis and Clark's map from their 1804-1806 expedition refers to Mount Rainier as Mt. Regniere. Sure the spelling was off, but the name was recognized. However, throughout the 19th century the mountain was called both Mount Rainier and Mount Tacoma. It wasn’t codified as “Rainier” until 1890, when the United States Board of Geographic Names deemed that it would be named after the British Admiral. As late as 1924, however, a resolution was introduced in the U.S. Congress to call it Tacoma.

The first people documented to have climbed Mount Rainier were Hazard Stevens and P.B. Van Trump, who successfully completed the ascent in 1870. The first female to complete the climb was Fay Fuller, in 1890. American naturalist John Muir climbed Mount Rainier in 1888. He wrote of the climb:

"The view we enjoyed from the summit could hardly be surpassed in sublimity and grandeur; but one feels far from home so high in the sky, so much so that one is inclined to guess that, apart from the acquisition of knowledge and the exhilaration of climbing, more pleasure is to be found at the foot of the mountains than on their tops. Doubly happy, however, is the man to whom lofty mountain tops are within reach, for the lights that shine there illumine all that lies below."

Approximately 13,000 people attempt to climb Mount Rainier each year, and it can take up to two to three days to climb to its summit. Its summits include Liberty Cap, Point Success, and Columbia Crest. From the top of the primary peak one can see a great distance, including Mount Hood, Glacier Peak, Mount Baker, Mount Adams, and Mount St. Helens which is around 90 miles away.