Wizard Island

Wizard Island is a volcanic cinder cone which forms an island at the west end of Crater Lake in Crater Lake National Park, Oregon. The top of the island reaches 6,933 feet above sea level, about 755 feet above the average surface of the lake. The cone is capped by a volcanic crater about 500 feet wide and 100 feet deep. The crater was named the "Witches Cauldron" by William Gladstone Steel in 1885, who also gave Wizard Island its name at the same time.
The land area of the island is 315.85 acres .

Wizard Island was created after Mount Mazama, a large complex volcano, erupted violently approximately 7,700 years ago, forming its caldera which now contains Crater Lake. Following the cataclysmic caldera-forming eruption, which left a hole about 4,000 feet deep where the mountain had once stood, a series of smaller eruptions over the next several hundred years formed several cinder cones on the caldera floor. The highest of these cones, the only one to rise above the current lake level, is Wizard Island, which rises over 2,700 feet above the lowest point on the caldera floor and the deepest point in the lake.

Wikipedia