We are OPEN 7 days a week 9:00AM-5:30PM


First tour leaves at 9:30AM and the last tour leaves at 5:00PM

Explore South Dakota's Biggest Mystery

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Mystery House
From $14

You'll wonder how it all works at this mysterious attraction where you can stand on the walls and balls roll uphill.

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Mystery House
Geode Mine
From $6

Pick up a hand spade and start digging for your very own geode!

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Geode Mine
Visit Us
From $14

Hours of fun for the whole family!

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Visit Us

Hours of Operation

We can get very busy during the summer. We strongly suggest that you purchase tickets online in advance to ensure you get a spot on one of our tours.

April & October - 9:30AM-4:00PM Friday, Saturday and Sunday (tours every hour from 10:00am-4:00pm)
May & September - 9:30AM-4:00PM (tours vary daily from 10AM-4PM)
June, July - 9:00AM - 5:00PM (tours vary from 9:30AM-5:00PM)
August 1st thru 31st - 9:30AM-5:00PM (Monday-Friday first tour at 10AM and last tour at 4PM) (Saturday and Sunday first tour at 10AM and last tour at 4:30PM) Tour times vary daily so please call ahead.
Holidays (Memorial day, 4th of July, Labor Day) - 9:00AM-5:00PM (tours every five-ten minutes from 9:30AM-5:00PM)

Don't forget to check out our Gem Mine during your visit!

Separate and recover gems, fossils, arrowheads and minerals using our sluice. Match your findings to your gem index to discover what types of rocks you’ve collected! A hands-on activity for the whole family to enjoy! We offer several different options of mining dirt in our Gift Shop.

More Information
Cosmos Mystery Area
Based on 2389 reviews
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Nataly LermaNataly Lerma
22:37 10 Jul 23
I really enjoy my time here always. This time my son was 7 years old and he had a blast. Our tour guide was super nice a d he let the children participate which we thought was pretty cool.
Luke SteffenLuke Steffen
22:42 04 Jul 23
This place was incredible fun. I have no issues with dizziness and this place threw off my equilibrium. It even took a few minutes after the tour to feel normal. The kids loved it.
chris hobelmanchris hobelman
00:29 03 Jul 23
Just a fun quick trip to this location. Nice gift shop with shirts and food. Restrooms are on location. Staff was awesome and so was our guide.
hodelia hayathodelia hayat
21:26 17 Jun 23
First off, WTH. Balls rolling uphill, water doesn’t follow gravity, a pushed weight goes more in one direction and walking on walls?!? Our tour guide was funny and good. The kids and us were so weirded out, but we can’t wait to go back!
Rachel JensonRachel Jenson
21:06 30 Apr 23
We really enjoyed Cosmos! The tour was great, it was such a fun little stop. Our tour guide Rileyn ( sp?) was great, very funny and engaging. Definitely recommend!

Our Story

In 1952, two college boys searched the Black Hills looking for the perfect spot to build a summer cabin. Upon their search, they stumbled into the mysterious world of the Cosmos.

Our Story