Wisconsin's oldest state park reveals Ice Age geology secrets

Angela Fitzgerald: We’re on the trails at Interstate Park, on the hunt to learn more about how the Ice Age shaped this layered landscape.

To do that, Natural Resource Property Supervisor Matthew Densow met me in the Ice Age Interpretive Center.

Matthew Densow: So, Interstate Park is a very, very unique property in that we are the oldest property in the state of Wisconsin. We have over 1,300 acres, and our major feature that we protect are the Dalles at the Saint Croix and the glacial potholes that we have here. We have 82 standard campsites along with two group campsites. We have a very nice swimming beach that’s on the Lake O’ the Dalles. We have over nine miles of hiking trail within the park. With the Ice Age Interpretive Center, it allows people to kind of travel back in time and experience what the area really kind of looked like, and then physically going on the pothole trails, imagining where the water was and how the potholes formed really kind of helps people transport back in time. So there’s lots to see and do here at Interstate.

Angela Fitzgerald: So, I understand there are technically two Interstate Parks.

Matthew Densow: So there is a Wisconsin Interstate and then there’s a Minnesota Interstate Park. So we’re the bigger, better one. You know, we have more to offer, more to see and do. There are some differences. They’re definitely both good properties to go and visit, but I’m gonna definitely advocate for our side.

Angela Fitzgerald: I’m all for friendly competition, so encouraging everyone to get outdoors, and they can option into the Interstate Park on the Wisconsin side, but clarifying the Interstate State Park is on the Minnesota side.

Matthew Densow: Correct.

Angela Fitzgerald: See both, but come here first.

Matthew Densow: Exactly.

Angela Fitzgerald: Okay. [both laughing] Thanks, Matthew.

Matthew Densow: Thanks.

Angela Fitzgerald: So I understand there’s a unique anniversary taking place this year, the 125th year of the park. Can you tell us about that?

Matthew Densow: Definitely. In September 20 of 1900, the first parcels of land were purchased here for Interstate Park. So this year is the 125th anniversary of Interstate Park, but also the entire Wisconsin state park system, which has grown from Interstate to 50 state parks, 15 state forests. Forty-four state trails, nine recreation areas, eight water resource areas, over 6,000 campsites, 1,500 buildings. It’s grown to what you see today.

Angela Fitzgerald: Would you mind showing me some more about the park?

Matthew Densow: Yeah, definitely. Let’s go for a nice little hike.

Angela Fitzgerald: From the center, we headed to the Pothole Trail to get a look at the ancient rock formations this park offers.

Matthew Densow: So, if you can imagine when everything was melting with the last glaciation, there’s a whole bunch of water that was coming through this area. Water was coming through really fast, and there’s lots of things that got caught in the water. Some of the ones that we find are called grinders.

Angela Fitzgerald: Oh, wow.

Matthew Densow: And this is a small example of one that we have here. Well, you get a whirlpool that forms, and then it drills into the rock itself.

Angela Fitzgerald: Oh!

Matthew Densow: And that’s how we form glacial potholes, which we have very fine examples here at Interstate Park. So one thing that makes potholes special, and you can tell it’s a pothole, is that the surface inside is smooth because you can tell that it’s been worn out.

Angela Fitzgerald: I now have a more positive association with potholes than what I came into this conversation with.

Matthew Densow: Great. It’s a fun feature, isn’t it?

Angela Fitzgerald: Absolutely. Something I never thought I’d say, I have a newfound admiration for potholes.

Matthew Densow: So, this is the Dalles.

Angela Fitzgerald: And for the majestic views found at Interstate Park, on the Wisconsin side.