Minnesota's Backyard: River views, billion-year-old rock formations draw visitors to Interstate State Park
The border between Minnesota and Wisconsin here was formed by a combination of molten lava and melting glaciers over the past billion years. The St. Croix River Valley's hugely popular public access site features hikes along the bluffs and down to the river, and ways to see these stunning rock cliffs from water level.
TAYLORS FALLS, Minn. — In roughly 99% of Minnesota, potholes are something people try to avoid, in spite of what that guy down at the new tire showroom might tell you.
Welcome to the 1%.
At Interstate State Park there are seemingly always improvements being made, but the primary attraction, namely the solid rock cliffs along the St. Croix River are roughly one billion (with a ‘b’) years old, formed when molten lava poked up through a fissure in the planet’s crust and hardened along what would become the Minnesota-Wisconsin border.
By contrast the river — which today divides the Land of 10,000 Lakes from America’s Dairyland — is a relatively new addition to the landscape, as it started flowing and carving a stunningly scenic trench in that solid rock only about 10,000 years ago. Like so much of the water that defines the state’s landscape, the St. Croix came along when melting glaciers helped create the valley.
As the river flowed, fast-moving eddies and whirlpools of water, sand and rock carved deep holes into the rock. Known today as “potholes,” these natural phenomena are far different than the road hazards that mean getting a front-end alignment job every spring. There are plenty of signs explaining the geology of the site and how these attractions formed, and naturalists on site offer daily 45-minute tours of the pothole area, for a deeper dive into the hows and whys.
“We’re one of the smaller state parks in the system but we’re one of the busiest because there are a lot of different attractions that people access, and the glacial potholes are definitely among the most popular,” said Jenni Webster, an interpretive naturalist at Interstate. Webster noted the surrounding landscape is dominated by rolling prairie until the river valley appears suddenly and dramatically.
“For a lot of people, maybe they’re coming from the Twin Cities and they’re driving down Highway 8 and you get just a mile away from the park and all of a sudden this valley opens up with rock outcrops as you get closer to the river,” she said. “It’s kind of a whole different world than the landscape around it and I think that’s kind of the appeal for some folks.”
While signs caution against swimming in the river and the dangers of jumping from the cliffs into the water, no matter how tempting that might seem on a hot day, there is water access in the form of tour boats and a private canoe rental outfitter that can set visitors up for a seven-mile paddle down the St. Croix, then pick them up in Osceola, Wisconsin, for a ride back to their vehicles.
Dedicated in 1895, just four years after Itasca became the flagship in the state park system, Interstate is Minnesota’s second-oldest such public park. On the other side of the St. Croix, Wisconsin’s sister state park (also named “Interstate”) is the oldest park in that state’s system. While there is a separate admission charge to visit both parks, it is common for hikers to get the view from both sides of the river on a nice day.
From the natural wonders in the St. Croix valley, it is less than a five-minute drive to a chance to hike among some of Minnesota’s most notable man-made wonders. At the Franconia Sculpture Park , visitors can wander and browse more than 100 large-scale works of art. This 50-acre outdoor museum was founded in 1996 and has golf carts for rent, offering those with limited mobility an easier way to see all that is on display there.
This article is part of the " Minnesota's Backyard " series which returns for the summer of 2022.