A volcano is probably the very last thing you would expect to find in Nebraska, but there is a volcano in our state’s history…kind of.

Just outside of Newcastle in Dixon county, a town called Ionia existed right on the banks of the Missouri River.

Google Maps The river has since changed course and no longer flows right next to the cliffs here - but before it changed course, the river significantly changed the landscape here and swept away our one and only “volcano.”

Long before white settlers came to the area, Native Americans noted the smoking hills.

Google Maps And when the Lewis and Clark expedition came through in 1804, they wrote that the land was “on fire” and too hot to touch.

The rock formation was 180 to 190 feet tall, an impressive sight to see from the river.

flickr/Internet Archive Book Images (This picture and the one below depict the remains of the “volcano” in 1908. As these events took place in the very early days of practical photography, no known pictures of the Ionia Volcano exist.)In 1839, French geographer J.N. Nicollet set out to prove that the hot, smoking hill was not in fact a volcano. His theory was that iron pyrite deposits in the hill were coming in contact with water, creating a chemical reaction that generated high heat.

Nicollet was correct; the smoke and intense heat were due to chemical reactions, not volcanic activity. However, settlers in the area still believed that the smoking hill was a volcano, and they feared an eventual eruption.

flickr/Internet Archive Book Images When an earthquake struck in 1877, settlers were sure that an eruption was imminent. However, massive flooding in 1878 put their fears to rest when the waters washed the “volcano” away. Unfortunately, the flooding also all but washed away the town of Ionia, after which the “volcano” was named.

Today, a marker commemorating this weird part of Nebraska history stands in Pfister Park in Newcastle.

Nebraska State Historical Society Park visitors can read all about the mysterious “volcano” and picture what it might have looked like there on the bluffs above the river.

Not all of Ionia and its “volcano” have been lost. Today, you can visit the Ionia overlook on the approximate site of the smoking hill, from which you can see Nebraska, South Dakota, and Iowa all at once.

Google Maps

The river has since changed course and no longer flows right next to the cliffs here - but before it changed course, the river significantly changed the landscape here and swept away our one and only “volcano.”

And when the Lewis and Clark expedition came through in 1804, they wrote that the land was “on fire” and too hot to touch.

flickr/Internet Archive Book Images

(This picture and the one below depict the remains of the “volcano” in 1908. As these events took place in the very early days of practical photography, no known pictures of the Ionia Volcano exist.)In 1839, French geographer J.N. Nicollet set out to prove that the hot, smoking hill was not in fact a volcano. His theory was that iron pyrite deposits in the hill were coming in contact with water, creating a chemical reaction that generated high heat.

When an earthquake struck in 1877, settlers were sure that an eruption was imminent. However, massive flooding in 1878 put their fears to rest when the waters washed the “volcano” away. Unfortunately, the flooding also all but washed away the town of Ionia, after which the “volcano” was named.

Nebraska State Historical Society

Park visitors can read all about the mysterious “volcano” and picture what it might have looked like there on the bluffs above the river.

This story is just one of the truly unusual things that have happened in Nebraska’s long history. For even more, take a look at our list of 8 bizarre things that have happened here.

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