"The loop hike around Paulina Lake is located in the 50,000-acre Newberry National Volcanic Monument, a national preserve that was established in 1990. At the heart of this national monument is the 500-square-mile Newberry Caldera crater, which houses Paulina and East Lakes. Paulina Lake (250 feet deep) and East Lake (180 feet deep) were a single very large lake until lava flows split them apart approximately 6,200 years ago.
Today these two lakes are designated as a wildlife refuge supporting bald eagles, ducks, geese, ospreys, and tundra swans. Mammals roaming the shores and surrounding peaks and valleys include badgers, black bears, deer, elk, and pine martens. These lakes are also popular with anglers, and you’ll most likely see them fishing for rainbow trout, brown trout, and blackwater trout. The blackwater trout were introduced to the lake to help control the populations of tui chub fish that have reproduced rapidly in Paulina and East Lakes and threaten the quality of the trout catch in both lakes."