Geological History of Yellowstone Lake
The volcanic chamber under what is now Yellowstone collapsed roughly 600,000 years ago. This formed the Yellowstone Caldera. Part of that caldera was filled by water and became known as Yellowstone Lake. Originally the lake was 200 feet higher than it is today. It reached up into Hayden Valley and to the base of Mount Washburn.
History of Yellowstone Lake Fishing
In 1872, about 40% of the park's waters were barren of fish. This eventually led to the construction of a two-story fish hatchery near Lake Hotel in 1912 and by 1920 the Director of National Parks indicated that the hatchery was doing its job of replenishing the fish supply. There is concern about preserving native fish species and the hatchery ends up shutting down in 1957 so that personnel could shift their attention to research only. Today there are strict regulations on fishing within park boundaries.
Stop by the Fishing Bridge Museum and learn more about Yellowstone Lake's history.