Alaska’s Lake Iliamna is the largest freshwater lake in Alaska and the second largest lake in the
United States.It is over 80 miles long with a surface area of more than 1,000 square miles and an average depth of 660 feet. It is connected to Bristol Bay by the Kvichak River. Marine mammals such as beluga whales and harbor seals are known to reach Lake Iliamna by traveling up this river.
Many of the world’s large lakes are said to be the homes of lake monsters, and Lake Iliamna is no exception. Aleuts and other indigenous people knew about these creatures, locally known as Illies, and did not venture to hunt them.
Although the Illies had been reported by early white settlers and other visitors to the lake, the creatures were relatively unknown until pilots began to report sightings from the air in the 1940s. The pilots described giant fish or whale-like creatures ranging in size from about ten to thirty feet long. Generally, they are described as being the color of dull aluminum, with broad, blunt heads. Their tails were vertical, unlike those of whales, and the creatures did not surface.
Some more recent reports describe the fish as black or very dark brown.
In 1959, oil tycoon Tom Slick funded a series of investigations around Lake Iliamna intended to establish the existence of the Illies. He also offered a $1,000 reward to anyone who managed to catch one. No one claimed the reward. The Anchorage Daily News offered a $100,000 reward for physical evidence of the monsters, but so far the reward has never been claimed.
Based on the descriptions, any people believe the monsters are actually gigantic lake sturgeon, which are known to grow to lengths of 20 feet and weigh around 1,800 pounds. The white sturgeon, for example, is the largest freshwater fish in North America. These giant fish are bottom feeders and are rarely seen near the surface of the lakes and deep rivers in which they live.
It is not likely that the Lake Iliamna monsters are either whales or seals. The reports do not indicate that these creatures surface for air, and their tails are invariably described as vertical. Marine mammals’ tails are universally horizontal.
So far, no major expeditions have been mounted to find and identify the mysterious monsters of Lake Iliamna, although Animal Planet’s “River Monsters” series did conduct an investigation which failed to identify the creatures. So the mystery of the Lake Iliamna monsters remains unsolved, at least for now.
There are several stories of sightings of these monsters at this site