Bridges Along I-35 Honor Monarch Migration in Iowa

It's the time of year when birds and insects start their great migration south to warmer climates.

And there's one interstate that runs through Iowa that transports more than just people and goods in semis.

I-35: The Monarch Trail

This time of year, Interstate 35 is becoming more than just a major travel route between Texas and Minnesota; it is transforming into a lifeline for one of North America’s most beloved winged migrants, the monarch butterfly.

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The interstate goes between six states: Texas, Oklahoma, Kansas, Missouri, Iowa, and Minnesota.

This effort aims to turn roadsides along I-35 into patches of sanctuary, with native wildflowers, milkweed for breeding, reduced mowing, and less heavy use of herbicides.

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The goal: to help monarch butterflies survive a dramatic decline in recent years.

The monarch population has slumped by nearly ninety percent over the last decades, losses driven by habitat loss, pesticide use, and climate change.

Because I-35 lies right in the “central flyway” of monarch migration, the route the butterflies use to travel between breeding grounds in the north and overwintering sites in Mexico, it offers one of the best opportunities for roadside habitat restoration.

1-35 in Iowa: a Monarch Haven

If you're driving north or south on I-35 between Ankeny and Ames, you’ll notice something rising over the highway, not just wider lanes and rebuilt bridges, but art, meaning, and a message baked into the very structure.

The “Monarch Highway Bridges” project has transformed seven overhead bridges along this stretch of I-35.

When Iowa DOT planners realized that the widening of I-35 would require replacing multiple bridges in the Ankeny-to-Ames corridor, the timing aligned with a larger regional initiative.

Designer Kimball Olson came up with the idea to integrate the Monarch theme into the bridge designs.

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Rather than just paint, the plan calls for colored veneer brick on each bridge’s central support pier.

These bricks will capture moments of the monarch’s wing pattern; each bridge will be slightly different, so drivers will see a progression of patterns along the route.

So, if you've seen these bridges and wondered why they look the way they do, now you know!

Save travels, monarchs! See you next year.

Hey, if you just don't want to let summer go, check out some of the best restaurants we tried this season!