Crater Lake

Crater Lake is a caldera lake located in the south-central region of the U.S. state of Oregon. It is the main feature of Crater Lake National Park and famous for its deep blue color and water clarity. The lake partly fills a nearly 2,148-foot (655 m) deep caldera that was formed around 7,700 (± 150) years ago by the collapse of the volcano Mount Mazama. There are no rivers flowing into or out of the lake; the evaporation is compensated for by rain and snowfall at a rate such that the total amount of water is replaced every 250 years.

On June 12, 1853, John Wesley Hillman was reportedly the first person of European descent to see what he named "Deep Blue Lake" in Oregon. The lake was renamed at least three times, as Blue Lake, Lake Majesty, and finally Crater Lake.

Crater Lake is known for the "Old Man of the Lake", a full-sized tree which is now a stump that has been bobbing vertically in the lake for more than a century. Due to the cold water, the tree has been rather well preserved.

While having no indigenous fish population, the lake was stocked from 1888 to 1941 with a variety of fish. Several species have formed self sustaining populations. Since 2002, one of the state's regular-issue license plate designs has featured Crater Lake. The commemorative Oregon State Quarter, which was released by the United States Mint in 2005, features an image of Crater Lake on its reverse.

A crater lake is a lake that forms in a volcanic crater or caldera, such as a maar; less commonly and with lower association to the term a lake may form in an impact crater caused by a meteorite. Sometimes lakes which form inside calderas are called caldera lakes, but often this distinction is not made. Crater lakes covering active (fumarolic) volcanic vents are sometimes known as volcanic lakes, and the water within them is often acidic, saturated with volcanic gases, and cloudy with a strong greenish color. Lakes located in dormant or extinct volcanoes tend to have fresh water, and the water clarity in such lakes can be exceptional due to the lack of inflowing streams and sediment.

Crater Lake National Park is a United States National Park located in southern Oregon. Established in 1902, Crater Lake National Park is the sixth oldest national park in the United States and the only one in the state of Oregon. The park encompasses the caldera of Crater Lake, a remnant of a destroyed volcano, Mount Mazama, and the surrounding hills and forests.

The lake is 1,949 feet (594 m) deep at its deepest point, which makes it the deepest lake in the United States, the second deepest in North America and the ninth deepest in the world. However, when comparing its average depth of 1,148 feet (350 m) to the average depth of other deep lakes, Crater Lake becomes the deepest in the Western Hemisphere and the third deepest in the world. The impressive average depth of this volcanic lake is due to the nearly symmetrical 4,000-foot (1,200 m) deep caldera formed 7,700 years ago during the violent climactic eruptions and subsequent collapse of Mount Mazama and the relatively moist climate that is typical of the crest of the Cascade Range.

The caldera rim ranges in elevation from 7,000 to 8,000 feet (2,100 to 2,400 m). The United States Geological Survey benchmarked elevation of the lake surface itself is 6,178 feet (1,883 m). This National Park encompasses 183,225 acres (286.29 sq mi; 741.49 km²). Crater Lake has no streams flowing into or out of it. All water that enters the lake is eventually lost from evaporation or subsurface seepage. The lake's water commonly has a striking blue hue, and the lake is re-filled entirely from direct precipitation in the form of snow and rain.

Mount Mazama is a destroyed stratovolcano in the Oregon part of the Cascade Volcanic Arc and the Cascade Range located in the United States. The volcano's collapsed caldera holds Crater Lake, and the entire mountain is located within Crater Lake National Park.

Mazama was destroyed by a volcanic eruption that occurred around 5,677 (± 150) BC. The eruption reduced Mazama's approximate 12,000-foot (3,700 m) height by around a mile (1600 m). Much of the volcano fell into the volcano's partially emptied neck and magma chamber. At 8,159 feet (2,487 m), Hillman Peak is now the highest point on the rim.