Somewhere along Interstate 25, between Larkspur and Monument in Douglas County, Colorado, something has changed.
A bridge has appeared. Not for cars — for everything else.
The I-25 Greenland Wildlife Overpass is now officially North America's largest wildlife crossing, and it's already doing its job. Elk are crossing. Mule deer are crossing. Pronghorn — the second-fastest land animal on Earth — are crossing the highway that once divided 39,000 acres of their habitat in half.
The structure is extraordinary. Two hundred feet wide and 209 feet long, it spans six lanes of one of Colorado's busiest interstates. It is not a thin footbridge designed to satisfy a checkbox. It is a genuine landscape corridor — planted with native grasses and shrubs, designed to feel, to an animal, like a continuation of the meadow on the other side.
And it was completed ahead of schedule. Under budget. In a construction sector and political environment not always associated with either.
The project forms the centrepiece of an 18-mile wildlife crossing system along this stretch of I-25 — a broader initiative aimed at reducing wildlife-vehicle collisions by 90 percent in the area. The Douglas County corridor is one of the most significant wildlife movement zones on Colorado's Front Range. Before the bridge, animals either risked the crossing on tarmac or didn't make it across at all. The genetic and ecological consequences of that isolation accumulate quietly over generations: smaller herds, reduced diversity, weakened populations.
The overpass reverses that. It reconnects fragmented habitat. It lets populations mingle. It lets animals be animals.
Colorado's Department of Transportation partnered with a coalition of wildlife groups, conservation agencies, and local stakeholders to make the project happen. It's the kind of infrastructure investment whose return on investment is measured not in traffic throughput, but in species resilience, collision prevention, and landscape health.
The title of 'North America's largest' may not last long — California's Wallis Annenberg Wildlife Crossing, spanning ten lanes of US-101 in the Santa Monica Mountains, is expected to be completed later in 2026. That project will be enormous, too.
But for now, the elk are crossing in Colorado. And that, on its own, is worth celebrating. 🦌