Crater Lake is located in the southern Cascade Mountains in Oregon, 100 miles (160 km) east of the Pacific Ocean. It became a National Park in 1902 and is still the only one in Oregon.
7,700 years ago Mt Mazama exploded in an eruption 42 times more powerful than the 1980 eruption of Mt St. Helens. The top 5,000 feet (1524 meters) of the mountain collapsed on itself forming a huge basin. Before the volcano became extinct, magma eventually sealed the bottom of the basin, but did not fill it, allowing rainfall and snowmelt to fill it.
Crater Lake contains about 4.6 trillion gallons (17.4 trillion liters) of water, and at a depth of 1,932 feet (589 meters) it is the seventh deepest lake in the world and is the deepest in the United States. Winter snowfall avaeraging 533 inches (1,354 cm) per year provide the water for the lake. Evaporation and seepage prevent the lake from becoming any deeper.
Many consider the lake to be the bluest water in the world, rivaled only by the ocean around Easter Island.