Witnesses have described the Flathead Lake Monster as being more than ten feet long, and some have reported as many as three humps on its back while swimming along the surface of the water.
Flathead Lake is the largest lake west of the Mississippi River if you consider Red Lake and Lake of the Woods to be north of the Mississippi rather than west of it. With a surface area of nearly two hundred square miles, Flathead Lake has a surface area slightly larger than Lake Tahoe. Its maximum depth is 370 feet, deeper than the average depths of the Yellow Sea or the Persian Gulf. Located in northwestern Montana, between Kalispell and Polson, the lake includes several islands.
It is said to be one of the most active bodies of water for lake monsters in North America, with traditions that seem to involve two separate types of cryptids.
The creature that is sometimes known as Flattie or Montana Nessie can be traced to Native American legends.
The first reported sighting of the lake monster by a European-American was by Captain James Kern in 1889. He reported encountering a whale-sized creature while piloting a steamboat across the lake. Another sighting was made from a steamboat in 1919. Since then, several reports have been made to the Montana Department of Fish, Wildlife and Parks. By 1998, there were seventy-eight reports on file. Eleven sightings were reported in 1993, and in 1998 a fisherman reporting seeing an unusually large animal in the water, which he estimated to be several feet long. His description of the creature's shape and tail fin might have fit that of a sturgeon, as have some of the other reports that have made.
Although some reports were of a creature resembling a whale, most were of a snake-like creature, from twenty to sixty feet in length, and characterized by humps and smooth skin, which would not correspond to that of a sturgeon or whale.
The majority of the reports received described a creature more akin to that of the Loch Ness Monster.
The lake has a large population of sturgeon, although others insist that there are no sturgeon in Flathead Lake. Nevertheless, the largest known sturgeon in Montana was seven feet, six inches, weighing a hundred and eighty-one pounds. Caught in 1955, it was displayed in the Polson-Flathead Historical Museum. If indeed, Flathead Lake does have a significant population of sturgeon, this might account for at least some of the sightings.
Millions of years ago, the area was covered by an inland sea that was inhabited by sharks and other very large fish, as well as by swimming reptiles. Might some of these creatures survived, evolving to become a freshwater creature? Is it a sturgeon? Or a figment of the imagination?
Fuller Laugher, a skin diver, spent four days in a row on the lake in 1964 without sighting anything particularly large, and another fisherman trolled the lake while baiting an oversized hook with whole chickens, catching nothing. That same year, a company known as Big Fish Unlimited offered $1,400 for anyone who could catch the Flathead Lake Monster or any fish larger than fourteen feet, and there were no takers.
Whether real, a hoax, or a case of mistaken identity, websites focused on the Flathead Lake Monster or any other unusually large water creatures in Flathead Lake are appropriate for this category.
 
 
Recommended Resources
Anomalien: Montana’s Flathead Lake Monster
The cryptozoology site offers an account of the lake creature said to inhabit Flathead Lake, on the southern tip of the Rocky Mountain Trench, in northwestern Montana. The appearance of the creature is discussed, according to various reports, and the first sighting, as well as other sightings, are posted, along with possible explanations for what people believe they are seeing, including the possibility that what they are seeing is a sturgeon or that another object is being misidentified.
https://anomalien.com/montanas-flathead-lake-monster/
Cryptid Wiki: Flathead Lake Monster
Using a wiki platform, the site offers information about several cryptids and non-cryptids. Its page on the Flathead Lake Monster includes an artist's rendering of the creature, and describes its appearance and location, making a comparison with that of the Loch Ness Monster. A brief description of the characteristics of the lake is given, and several reported sightings are discussed, both historical and contemporary. Comments may be added by site visitors.
https://cryptidz.fandom.com/wiki/Flathead_Lake_Monster
Flathead Beacon: The History of a Monster
The local newspaper, published in Kalispell, Montana, published an article on August 29, 2007, discussing the findings of Laney Hanzel, who began recording eyewitness accounts of the Flathead Lake Monster in 1990, while he was employed by the Montana Fish, Wildlife and Parks department, and has spent even more time on the project since his retirement in 1993. Several accounts, sightings, and theories about the nature of the creature are discussed.
https://flatheadbeacon.com/2007/08/29/the-history-of-a-monster/
Flathead Lake: 4 Astonishing Facts to Know
Flathead Lake is a clear water lake, one of Montana's most attractive, and one of the most frequently visited places. It is also rumored to be the home of a lake monster. The site discusses the history of the lake, gives geographical facts, and discusses the Flathead Lake Monster, which began as a Native American legend and has had several European-American sightings over the centuries. Fun things to do while visiting the lake are also presented, monster or no monster.
https://icytales.com/flathead-lake-4-astonishing-facts-to-know/
Flathead Lakers: Flathead Lake Monster
Incorporated in 1958, the Flathead Lakers was created to protect the water quality and the lake itself. The organization's website includes a page on the cryptozoological lake creature known as the Flathead Lake Monster, including a map showing areas of the lake where seventy-nine sightings have been reported, seventy percent of whom described the creature as a large eel-shaped creature from twenty to forty feet in length, other describing it as a large fish.
https://www.flatheadlakers.org/flathead-lake-monster/
Nessie - Our Flathead Lake Monster
According to legend, sightings of Nessie, the Flathead Lake, Montana version of the Loch Ness Monster, go back to the earliest days of human habitation in the area and even beyond, and multiple sightings of the creature are reported each year. The Polson Flathead Museum in Polson, Montana has a seven and one-half foot sturgeon, caught in Flathead Lake in 1955, mounted on its wall, and a suggestion is made that this may be the monster of the legends, although many disagree.
http://www.polsonflatheadmuseum.org/the-flathead-lake-monster/