FIELD FILE · OKOBOJI-LAKE-MONSTERLAKE & SEA MONSTERLOCAL LEGEND
Okoboji Lake Monster
Also known as Obojoki, East Okoboji Sea Serpent
Nicknamed Obojoki, a giant serpent or fish said to churn the waters of the Okoboji Lakes in northwest Iowa’s resort country since 1903.
The Iowa Great Lakes – a cluster of glacial lakes in Dickinson County that includes West and East Okoboji and Spirit Lake – have been a summer resort since the late 1800s, and like many resort lakes they acquired a monster. Locals call it Obojoki: a huge, dark creature said to surge through the water, rock small boats and vanish.
The earliest known report appeared in the Estherville Vindicator and Republican on July 3, 1903, under the headline “Is It a Sea Serpent?” A couple named Bartlett, out fishing on East Okoboji, described a violent commotion moving quickly near the surface. Whatever caused it seemed as large as an overturned skiff, and its waves were big enough that Mr. Bartlett feared his boat would be swamped. The paper wryly noted that nearly every fashionable resort had a sea serpent, so why not Okoboji?
Later tellings grew the creature to fantastic size – some describe it as 140 feet long, green or bluish-gray and scaly, with a head the size of a bowling ball – and added the claim that the lakes connect to the Gulf of Mexico through an underground river. Writers have described the legend as part tourist-industry invention, part older lore, and it has been passed around in local magazines, websites and online videos.
There is a real giant in the story, though. Paddlefish – large, long-snouted, plankton-eating fish – once reached the Okoboji Lakes from the Missouri River by way of the Little Sioux River. According to the Iowa Great Lakes Maritime Museum, the last and largest was caught in 1919: a 210-pound fish about six and a half feet long. A replica of that record fish is displayed at the museum in Arnolds Park, a reminder that the lakes really did once hold monsters of a sort.
- Status
- Local legend
- First reported
- 1903
- Best-known location
- Okoboji Lakes, Iowa Great Lakes, Dickinson County, Iowa
- Also called
- Obojoki, East Okoboji Sea Serpent
- Reported in
- Iowa
What witnesses describe
Described as a very large, fast-moving animal – anything from a fish the size of an overturned skiff to a 140-foot green or bluish-gray serpent with scales and a bowling-ball-sized head. Most reports describe a wake or disturbance more than a clear view of the animal.
Where and when it’s seen
East and West Okoboji Lakes and neighboring Spirit Lake in northwest Iowa, typically reported by boaters and anglers during the summer resort season.
Notable sightings
- July 3, 1903“Is It a Sea Serpent?” East Okoboji Lake, Iowa
The Estherville Vindicator and Republican reported that Mr. and Mrs. Charles Bartlett, fishing a few days earlier, saw a huge, fast-moving disturbance near the surface. The waves it raised alarmed them, but they could not say what caused it.
- 1919The last Okoboji paddlefish Okoboji Lakes, Iowa
A 210-pound, roughly six-and-a-half-foot paddlefish – the largest fish ever recorded from the Okoboji Lakes – was caught. It was the last of the species taken there, after a dam cut off the fish’s route from the Missouri River.
What could explain it?
- Paddlefish weighing up to 200 pounds or more lived in the Okoboji Lakes until about 1919 and could easily produce a large, startling wake.
- Large fish such as muskellunge, carp or catfish, wind-driven waves and boat wakes can create sudden surface commotions.
- Early-1900s resort newspapers often ran tongue-in-cheek “sea serpent” stories, and the 1903 article itself treated the idea lightly.
- Embellishments such as a 140-foot length or an underground river to the Gulf of Mexico are later folklore with no physical basis.
Legend, culture and tourism
Obojoki is a fixture of Okoboji summer lore, discussed in local magazines and tourist chatter. The Iowa Great Lakes Maritime Museum at Arnolds Park, on the shore of West Okoboji, displays a replica of the record 1919 paddlefish and shares both the real and legendary “lake monsters” with visitors.
Places to visit
Lake-history museum with antique boats and a replica of the giant 1919 Okoboji paddlefish.
Where it’s reported
Okoboji Lake Monster in the news
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Sources
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