13 Lake & River Monsters in North America

We are 100% reader supported. We may earn commission at no extra cost to you if you buy through a link on this page. Read our disclosure.

Loch Ness Monster sculpture
The Loch Ness Monster isn’t the only lake monster out there — there have been numerous sightings of other mysterious creatures in North America, too! MOs810, CC BY-SA 4.0, via Wikimedia Commons

There is something about lakes and rivers that spurs the imagination. It’s only human nature to look at such cool, deep waters and wonder if something strange and supernatural lurks beneath the surface. There’s a reason the legend of the Loch Ness Monster is so pervasive, after all!

But what about the New World? Do North American waters share something just as mysterious? Stories of these mythical serpents and monsters have been shared by Native Americans and First Nations people for hundreds of years, and sightings of unusual creatures are reported to this day.

This article will examine several famous lake and river monsters found in North America that give Nessie a run for her money!

1) Chessie

Chessie coloring book
Chessie is well-loved by Maryland locals and is used in coloring books by the U.S. Fish & Wildlife Service! Britt Eckardt Slattery, Public domain, via Wikimedia Commons
  • Description: Dark, snake-like monster
  • Reported location: Chesapeake Bay
  • First documented: 1936
  • Last seen: 2014
  • Possible explanation: Plesiosaur, eel, manatees

Possibly the most famous lake monster in North America, Chessie is described as a black, serpentine monster roughly 20 to 30 feet long with a football-shaped head or horse-like head. The creature was originally spotted in 1936 by a military helicopter but began being spotted frequently throughout the 70s, 80s, and 90s. Chessie has since been reported sporadically throughout the years, as recently as 2014.

Although sightings of it were originally met with fear or awe, Chessie has become an environmental icon in its native Maryland. It has been used in coloring books by the U.S. Fish and Wildlife Service as well as in articles and government publications on environmental issues. Chessie is beloved by locals and has been used as a mascot for little league teams, inspiration for costumes, and even the namesake for a manatee rescued in 1994.

2) Ogopogo

Ogopogo statue
It is thought that the Ogopogo is a serpentine creature with multiple humps. GoToVan from Vancouver, Canada, CC BY 2.0, via Wikimedia Commons
  • Description: Green or black serpent with smooth skin
  • Reported location: Okanagan Lake, British Columbia
  • First documented: 1872
  • Last seen: 2018
  • Possible explanation: Thermal wave

The Ogopogo is a famous monster with a variety of descriptions and purported origins. Despite being considered one of the best-documented of all lake monsters by cryptozoologists, the specifics of the creature’s existence are marred in controversy.

Native Okanagan speak of a sacred water being with black skin, a horse head, and antlers, known as nx̌ax̌aitkʷ. This being is said to have power over the lake and even the air around it, granting protection to travelers if it is fed and honored with live sacrifices into the lake.

Cryptozoologists, meanwhile, refer to the creature as Ogopogo after an English folk song. Most reports describe it as being a serpentine creature with smooth green or black skin and characteristic humps as it swims.

Some believe that the lore of the modern Ogopogo is a misinterpretation and commercialization of nx̌ax̌aitkʷ by settlers, while others say that Ogopogo sightings are illusions caused by thermal waves.

3) Champ

Illustration of Champ lake monster
Champ is a serpent-like monster that was first spotted in 1819. BRad06, CC BY-SA 4.0, via Wikimedia Commons
  • Description: Plesiosaur-like or serpent-like monster
  • Reported location: Lake Champlain
  • First documented: 1819
  • Last seen: 2005
  • Possible explanation: Lake sturgeon or gar

Champ is a large serpent-like monster, purported to inhabit Lake Champlain. The exact date that Champ was first witnessed is convoluted, with some claims arguing as early as the 1600s. More commonly, cryptozoologists agree that the first recorded sighting was in 1819 when Champ was described as an enormous serpentine monster with three sharp teeth, a star on its head, and shiny scales. Champ continued to be reported throughout the century, and searching for him became a popular pastime.

After three major sightings in 1873, Champ became a national curiosity. In an attempt to cash in on this fame, showman P. T. Barnum placed a ransom of 20 thousand dollars on its corpse, to no avail.

Champ was regularly seen throughout the 1900s, with a total of 180 sightings and 600 witnesses by 1992. Champ continues to be spotted to this day, but think twice about hunting it! Per state law of both Vermont and New York, Champ is a protected creature that cannot be legally harmed.

4) Cressie

Cressie lake monster statue
Cressie is often described as an eel-like creature with a head that resembles a fish. HeritageNL, CC BY-SA 4.0, via Wikimedia Commons
  • Description: Eel-like monster with a fish-like head
  • Reported location: Crescent Lake and surrounding waters, Canada
  • First documented: 1950s
  • Last seen: 2003
  • Possible explanation: Giant eels or logs

First spotted in the 1950s, Cressie is described as a brown eel-like monster that is 20 – 40 feet long with a fish-like head. Since the original reports, regular sightings have been reported, with a specific incident gathering extra attention.

In the mid-80s, several RCMP divers entered Crescent Lake in the hopes of finding the body of a pilot following a plane crash. But rather than finding the downed captain, the divers were forced to leave after being swarmed and attacked by a school of massive eels as thick as a thigh.

Many believe these eels were Cressie babies, and they are now often reported alongside Cressie. On the other hand, skeptics such as George Eberhart believe that these sightings were of oversized American eels, as they are known to inhabit these waters. As for Cressie herself, local historians point to sunken logs from Crescent Lake’s historical logging days that are known to resurface.

Whether or not she exists or is a tall tale is unknown, but locals adore their lake monster and built a large statue in her honor in 1991.

5) Altamaha-ha

Illustration of Altamaha-ha lake monster
It is thought that Altamaha-ha has front flippers and swims like a dolphin. Carnby, CC BY-SA 4.0, via Wikimedia Commons
  • Description: Green plesiosaur with an alligator head
  • Reported location: Tributaries of Altamaha River, Georgia
  • First documented: 1830
  • Last seen: 2018
  • Possible explanation: Alligator gar

The Altamaha-ha is a legendary green or gray plesiosaur-like monster with sharp teeth and an alligator-like head. It is said to have front flippers, and no back limbs, swimming much like a dolphin. The creature, which is often reported to be over 20 feet long, is believed to travel throughout the Altamaha River as well as its major tributaries.

Stories of the Altamaha-ha have persisted in Muscogee culture for centuries, where the creature is said to be protective rather than dangerous. Non-native reports of the creature were recorded in 1830, with more sightings occurring throughout the 1900s.

While most scientists maintain that the Altamaha-ha is likely a large alligator gar, many were thrown for a loop when a large plesiosaur-like corpse was found washed up. This was later proven to be a hoax by performance artist Zardulu, and sightings persist.

6) Bear Lake Monster

  • Description: Brown serpentine monster
  • Reported location: Bear Lake, Idaho-Utah border
  • First documented: 1868
  • Last seen: 2002
  • Possible explanation: Hoax

The Bear Lake Monster was first documented in 1868 by Joseph Rich, a Mormon settler, in the local Deseret News. Per the description Rich claimed to have been given by natives, the creature was said to be a large, brown serpent with small legs and a head like a cow, alligator, or tusk-less walrus.

Following the article’s publication, a frenzy began to try and capture or spot the beast, with even the LDS Church getting involved. Rich continued to write about the Bear Lake Monster, only admitting 26 years later that he had fabricated the story as a marketing ploy.

Despite this, sightings of the Bear Lake Monster are still reported sporadically, with the most recently reported sighting as late as 2002. While many locals doubt its existence, the Bear Lake Monster is still embraced and accepted by locals and has even been named Isabella per the suggestion of an 8-year-old girl.

7) Walgren Lake Monster

Walgren Lake Monster
The Walgren Lake Monster is thought to be a hoax, created by John G. Maher to encourage newspaper sales. Photo from History Nebraska
  • Description: Varying descriptions
  • Reported location: Walgren Lake, Nebraska
  • First documented: 1921
  • Last seen: 1985
  • Possible explanation: Hoax

Also known as the Alkali Lake Monster, the Walgren Lake Monster is a semi-aquatic beast that has been spotted since 1921, with a variety of descriptions. During its first few reports, the Walgren Lake Monster was often described as a 20-foot-long, whale-like or mermaid-like creature that spat water into the air. As interest picked up in the creature, its description rapidly became extreme, and it was described as a 40 – 100 foot alligator, mudskipper, or serpent with a strong stench and a large horn.

By 1938, an article described the Walgren Lake Monster (now christened Giganticus Brutervious) as having green eyes that spit fire, making the earth tremble when it walked, and the ability to create green mist.

Although some claim to have seen the monster as recently as 1985, it is thought to have been distributed and created by John G. Maher. Maher, a newspaperman and politician, was known to be behind a variety of sensationalist stories to sell newspapers.

8) Flathead Lake Monster

Flathead Lake Monster illustration
The Flathead Lake Monster is described as eel-like with steel-black eyes. Photo from Outside Bozeman
  • Description: Eel-like monster
  • Reported location: Flathead Lake, Montana
  • First documented: 1889
  • Last seen: 2017
  • Possible explanation: Sturgeon

Known lovingly by locals as Flossie, the Flathead Lake Monster is one of the most commonly seen lake and river monsters in North America. Over the 129 years since it was originally reported in 1889, the monster has been spotted over 109 times. 13 of those sightings occurred in a single year, 1993, and were remarkably consistent in their descriptions.

The Flathead Lake Monster is described as an undulating serpent, 20 to 40 feet long, with steel-black eyes. On occasion, it is reported to have 5 fins or resemble a sturgeon. Regardless of the specifics, observers typically agree that it is a shy, reclusive monster that means no harm. One 3-year-old claimed to have been saved by the creature after falling into the water.

9) Iliamna Lake Monster

Iliamna Lake Monster drawing
The Iliamna Lake Monster is a shark-like creature, and may actually be a Pacific sleeper shark. Photo from Pride of Bristol Bay Illustration by Alex Witt
  • Description: Dark, shark-like creature(s)
  • Reported location: Iliamna Lake, Alaska
  • First documented: Late 1940s
  • Last seen: 2020
  • Possible explanation: Sturgeon, Pacific sleeper shark, northern pike

While the first sightings of this shark-like beast were only officially documented in the 1940s, Yup’ik legend has long proclaimed the presence of a mythical dark fish in Iliamna Lake, which is known to bite holes in canoes.

Iliamna Lake Monsters are reported as being 10 to 20 feet long and are said to hunt in groups, preying on sockeye salmon and herding seals. With so many first-hand accounts from reputable individuals, many local scientists and ecologists believe that there is something lurking in the depths of the lake, but that it is not cryptozoological.

The most common explanation given is that Iliamna Lake hosts the northernmost population of lake sturgeon in the world, but some experts believe that the lake may house ancient Pacific sleeper fish that have become adapted to freshwater, or even a population of oversized northern pike.

With historical rewards as large as $100,000 for a corpse, cryptozoologists have long sought the creatures out. In 2019, underwater cameras and even the use of DNA sampling technology were deployed in the search.

10) Beast of Busco

Beast of Busco illustration
The Beast of Busco was a giant snapping turtle that was first spotted in 1898. It hasn’t been seen since 1949. Photo from the Encyclopaedia of Cryptozoology
  • Description: Massive common snapping turtle
  • Reported location: Fulk Lake in Churubusco, Indiana
  • First documented: 1898
  • Last seen: 1949
  • Possible explanation: Alligator snapping turtle

The Beast of Busco was a massive common snapping turtle spotted in 1898 by Oscar Fulk, who saw the creature in a 7-acre lake on his farm. Despite having an estimated weight of 500 pounds, the Beast of Busco did not grab attention when it was originally sighted.

50 years later, locals Ora Blue and Charley Wilson saw the creature as they were fishing on the same lake. This report gathered national attention, spurring a massive search for the beast. In one attempt to capture the Beast of Busco, over 100 people claimed to have seen the gigantic turtle.

Gale Harris, a farmer who owned the property the Beast of Busco purportedly inhabited, became fixated on finding the monster, using traps and scuba divers initially. Later, attempts were made to drain the lake to no avail.

The search was then given up and the creature has not been reported since. Some theorize the Beast of Busco was actually an alligator snapping turtle who had migrated north in its old age. Alligator snapping turtles are known to surpass 200 pounds but are usually found south of Indiana.

11) Mugwump

  • Description: Snake-like monster with a horse head
  • Reported location: Lake Timiskaming, Canada
  • First documented: 1979
  • Last seen: 2015
  • Possible explanation: Sturgeon, group of otters

According to Mayor Jack Dent in the 1979 newspaper article that introduced the cryptid to the public eye, the term “Mugwump” is derived from an Algonquin word that purportedly means “fearless sturgeon.”

As its title would suggest, the Mugwump was once described as being a massive lake sturgeon, but modern reports consistently describe the Mugwump as a green, brown, or gray legless beast surpassing 50 feet.

After its introduction in the late 70s, newspapers picked up the story of the Mugwump and began sensationalizing the story, with journalist Ada Arney reporting heavily on the creature under a variety of aliases, such as Alice Peeper and fake biologists and cryptozoologists.

Despite the clear misdirection of these articles, sightings of the Mugwump were still regular throughout the summer in the 80s, and still occur occasionally, with a 2015 video claiming to have caught it on camera. Some believe that witnesses saw a sturgeon or even a group of otters swimming in a single file line.

12) Sharlie

Sharlie statue
Sharlie has a humped back and a dinosaur-like head. cifraser1 / CC BY 2.0
  • Description: Sea serpent with pronounced jaws, humps, and a dinosaur-like head
  • Reported location: Payette Lake, Idaho
  • First documented: 1920
  • Last seen: 2019
  • Possible explanation: Lake sturgeon, plesiosaur

Sharlie, known previously as Slimy Slim, is a serpentine lake monster first spotted in the 1920s by a logging crew. She remained mostly out of the limelight until a major sighting in 1944 by a small group, who described her as thirty to forty feet long, with a dinosaur-like head and a humped back.

The creature was seen frequently throughout the 40s and 50s, spurring a naming contest in 1954. The name Sharlie was chosen for the serpent, with the winning entry reading, “Why don’t you call him Sharlie? You know, like ‘Vas you der, Sharlie?’” in reference to a famous one-liner by radio host Jack Pearl.

Sharlie continues to be seen to this day, with the latest recorded sighting in 2019, almost 100 years after the original. Regardless of if locals believe in her existence or not, Sharlie has become something of an icon in McCall, making an annual appearance as an ice sculpture in the Winter Carnival Parade.

13) White River Monster

Illustration of the White River Monster
The White River Monster is a gray-skinned creature that was last seen in 1973. Photo from the Cryptid Wiki
  • Description: Gray fish-like creature
  • Reported location: White River, Arkansas
  • First documented: 1915
  • Last seen: 1973
  • Possible explanation: Elephant seal, Florida manatee

The White River Monster is a gray-skinned creature said to be “as wide as a car and three cars long.” It is described by some to have elephant-like skin or peeling flesh and three-toed tracks.

It was spotted sporadically throughout the early 1900s, but a report in 1937 spawned a frenzy to find the creature with the use of dynamite, machine guns, and more. A diver was even hired by the city to swim through the lake in search of the creature, and a large net was planned to be built to capture it. After funds became lacking, the hype died down.

The monster wasn’t officially seen again until 1971, when it was reported to have a bone in the middle of its head. Two years later, in 1973, the area between Old Grand Glaize and the northern point of White River was designated as the White River Monster Refuge, in which it is illegal to harm the monster.

Angeline L
About the author

Angeline L

I'm a passionate researcher and scuba diver with a keen interest in garden plants, marine life, and freshwater ecology. I think there’s nothing better than a day spent writing in nature. I have an academic and professional background in sustainable aquaculture, so I advocate for the responsible production of commercial fish, macroinvertebrates, and aquatic plants.

Read more about Pond Informer.

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.