Devil’s Kettle


Useful Information

Location: Hovland, MN 55606.
From Duluth Highway 61 along the north coast of Lake Superior 196 km, turnoff signposted.
(47.8292691, -90.0495652)
Open: All year daily 8-22.
[2025]
Fee: Car USD 7.
[2025]
Classification: GeologyPothole
Light: n/a
Dimension:
Guided tours: self guided
Photography: allowed
Accessibility: no
Bibliography:
Address: Judge C.R. Magney State Park, 4051 East Highway 61, Grand Marais, MN 55604, Tel: +1-218-387-6300. E-mail:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
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History

1934 transient work camp built by the State to provide work and lodging for men displaced during the Depression years.
1935 men helped fight a fire which burned more than 10,000 acres in the area.
1957 Brule River State Park created.
1963 renamed Judge C.R. Magney State Park as a memorial to the late judge, mayor of Duluth, justice of the Minnesota Supreme Court, and a strong advocate of Minnesota state parks.
2016 hydrologists from the Minnesota Department of Natural Resources (DNR) find nearly identical volumes of water above the Devil’s Kettle waterfall and below it.

Description

Devil’s Kettle is a weird site, a waterfall which vanishes underground. There are numerous YouTube videos in which it is sold as a great mystery, a kind of esoteric or metaphysical place. Reality is definitely interesting and exceptional, but there is a simple scientific explanation for it.

But let’s start with the obvious details. The Brule River is a tributary of Lake Superior. In the Judge C. R. Magney State Park, there is a strange waterfall named the Kettle Falls. The river first splits into two at a large rock outcropping. A gorge follows, and the left arm of the river drops as a normal waterfall 15 m deep and then flows again as a river. But the right arm flows into a sort of pothole and vanishes. And if you throw a marker like a swimming ping pong ball or a stick into the pothole, it vanishes forever.

This weird fact easily explains why the site got the name Devil’s Kettle. Superstitious people believed that the water vanished because it went to hell through the pothole. The obvious explanation is though, there must be a cave and the water flows underground through the cave and reappears somewhere as a spring. But now the enigma starts: first of all the rocks are not suitable for the formation of caves. The rocks in the area are volcanic rocks from the Precambrian, about 1.1 billion years old. There are alternating layers of basalt and rhyolite, which were erupted from the Midcontinent Rift System. There are also intrusions of gabbro and diabase in the north and ferrodiorite in the south. Here at the waterfall its rhyolite with an estimated thickness of 240 m. Only cave formation which does not depend on the rock, mechanical erosion and tectonic forces, are possible here.

Then there is no source nearby, especially none with the right amount of water. And the last strange fact, which is actually the solution of the riddle: the amount of water below the waterfall in the gorge is the same as above. So the explanation is quite simple: the pothole is as deep as the plunge pool, and there is obviously a connection underwater. So the two branches meet at the bottom of the plunge pool, and the whole river flows down the valley.

The obvious question is now, how did this pothole form? It is not a karst cave, it is obviously an erosional form, as erosion works with any kind of rock. The formation of a waterfall has certain rules. It’s necessary to have a harder layer on top and a weaker layer below. The waterfall erodes in the plunge pool and even forms a waterfall cave, then the harder rock on top falls down if it protrudes too far. Slowly the waterfall moves upstream, this effect is called retrograde erosion. And a second thing: there is often a round hole which is formed by the water of a river in the riverbed. It has numerous names, but all have something to do with pothole or kettle. The flowing river produces a whirlpool, which causes the water to always transport its load of sand and gravel in a circle at the same point. This continuous movement is drilling a large hole in the riverbed, this creates a pothole.

Probably you have already connected all the puzzle pieces, actually it is rather simple. The river flowing through the gorge with some speed had whirlpools which drilled potholes in the riverbed. The river split at this point due to the huge rock in the middle of the riverbed. Probably this intensified the whirlpool. The retrograde erosion moved the waterfall towards the pothole, but for some reason the rocks on the left branch were weaker, so it moved in this direction. But when the falling water plunged into the plunge pool, it was widened in all directions, and it connected with the lower end of the pothole. So the water of the right branch started to flow through the pothole and then into the neighbouring plunge pool.

This situation is obviously quite rare, there are numerous things which must work together in the right way. And there is only a short period of time when the water actually flows through the pothole. Erosion goes on and the current situation will end soon enough. On the other hand, there is no sign of a devilish influence at all.

However, despite the rather simple concept and the obvious solution, the mystery has long fueled speculations. There were rumours that the water flows underground to Canada. Trump would not be happy and charge them. It seems people were also irritated by the vanishing markers, which is actually not mysterious at all. Solid markers never work well in caves. In this case there is a plunge pool at the bottom of the pothole, and the water actually presses anything to the floor and crashes it into small pieces, and that how all this stuff vanished. The only scientifically valid approach would be a dye tracing experiment. The hydrologists Jeff Green from the Minnesota Department of Natural Resources (DNR) and Calvin Alexander from the University of Minnesota planned such an experiment. But this requires permissions by the park authorities, and at first they researched a different approach. In 2016, they measured the water flow above the falls and below them. This strongly indicated that the disappearing water simply flows back into the Brule River. The dye tracing would have confirmed this theory and also revealed the exact location where the underground channel rejoins the main river. Unfortunately the park management refused the permit, and so the examination was not completed. The dye is used worldwide, is biodegradable and absolutely harmless, and as it is fluorescent, it’s easy to see, and it’s possible to measure with sensors. Why they refused is unclear, we guess they try to save the mystery.

The Judge C. R. Magney State Park was selected as a memorial to the late Judge Magney in 1963 by the Minnesota legislature. He was lawyer, mayor of Duluth, justice of the Minnesota Supreme Court, and a strong advocate of Minnesota state parks. He was instrumental in establishing 11 state parks and waysides along Lake Superior.

The park campground is located at a place where concrete foundations can be seen. Those are the remnants of a transient work camp built by the State in 1934. It was intended to provide work and lodging for men displaced during the Depression years, similar to the CCC. The men worked by building trails, logging, and completing public service projects. When a fire broke out in 1935 and destroyed 10,000 acres of forest, they helped fight the fire. And afterwards they set up a sawmill and salvaged the fire-damaged wood.

The car park is the trailhead of several hiking trails, one of them is the Superior Hiking Trail. Its first section is also called the Devil’s Kettle Trail. It is 1.6 km to the Devil’s Kettle along the Brule River, the trail has 175 stairs. There are two more waterfalls along the way, the Lower Falls and the Upper Falls. You should plan to spend 1.5 to 2 hours for the whole trip. The park and hiking trail are open all year round, but there is snow in winter, so make sure you wear appropriate clothing.