Geyser
Yellowstone is the largest geyser locale, containing thousands of hot springs, and approximately 300 to 500 geysers. It is home to half of the world's total number of geysers in its nine geyser basins. It is located mostly in Wyoming, USA, with small portions in Montana and Idaho. Yellowstone includes the world's tallest active geyser (Steamboat Geyser in Norris Geyser Basin), as well as the renowned Old Faithful Geyser, Beehive Geyser, Giantess Geyser, Lion Geyser, Plume Geyser, Aurum Geyser, Castle Geyser, Sawmill Geyser, Grand Geyser, Oblong Geyser, Giant Geyser, Daisy Geyser, Grotto Geyser, the Fan & Mortar Geysers, & the Riverside Geyser, all in the Upper Geyser Basin which alone contains nearly 180 geysers.
Cascade Volcanoes
During the mid-19th century, Mount Baker erupted for the first time in several thousand years. Fumarole activity remains in Sherman Crater, just south of the volcano's summit, became more intense in 1975 and is still energetic. However, an eruption is not expected in the near future.Glacier Peak last erupted about 200–300 years ago and has erupted about six times in the past 4,000 years.Mount Rainier last erupted between 1824 and 1854, but many eyewitnesses reported eruptive activity in 1858, 1870, 1879, 1882 and in 1894 as well. Mount Rainier has created at least four eruptions and many lahars in the past 4,000 years.Mount Adams was last active about 1,000 years ago and has created few eruptions during the past several thousand years, resulting in several major lava flows, the most notable being the A. G. Aiken Lava Bed, the Muddy Fork Lava Flows, and the Takh Takh Lava Flow. One of the most recent flows issued from South Butte created the long by wide A.G. Aiken Lava Bed. Thermal anomalies (hot spots) and gas emissions (including hydrogen sulfide) have occurred especially on the summit plateau since the Great Slide of 1921.Mount Hood was last active about 200 years ago, creating pyroclastic flows, lahars, and a well-known lava dome close to its peak called Crater Rock. Between 1856 and 1865, a sequence of steam explosions took place at Mount Hood.A great deal of volcanic activity has occurred at Newberry Volcano, which was last active about 1,300 years ago. It has one of the largest collections of cinder cones, lava domes, lava flows and fissures in the world.Medicine Lake Volcano has erupted about eight times in the past 4,000 years and was last active about 1,000 years ago when rhyolite and dacite erupted at Glass Mountain and associated vents near the caldera's eastern rim.Mount Shasta last erupted in 1786 and has been the most active volcano in California for about 4,000 years, erupting once every 300 years. The 1786 eruption created a pyroclastic flow, a lahar and three cold lahars, which streamed down Shasta's east flank via Ash Creek. A separate hot lahar went down Mud Creek.