A lake of southwest Oregon in a volcanic crater of the Cascade Range. At 589.3 m (1,932 ft) deep, it is the second-deepest lake in North America and the deepest in the United States. The lake and surrounding parkland are popular tourist attractions. Lake, Cascade Range, southwestern Oregon, U.S. The lake is in a huge volcanic caldera 6 mi (10 km) in diameter and 1,932 ft (589 m) deep. It is the remnant of a mountain destroyed in an eruption more than 6,000 years ago. The intensely blue lake and its surrounding region became a national park in 1902; the park covers 250 sq mi (647 sq km)