Deer Found California’s New Wildlife Bridge Before It Officially Opened

Before the last landscaping was finished, the bridge found its first travelers. Three deer crossed a newly built wildlife overpass on U.S. 97 in Northern California in late May 2026 — weeks before construction is scheduled to be complete. A bobcat followed. Caltrans District 2, which built the structure, called the sightings “a major milestone” and said it was “incredible to see wildlife already embracing the new structure” while contractors were still putting on finishing touches.

The crossing sits in Siskiyou County near Grass Lake, a remote stretch of highway in the shadow of Mount Shasta that has long been one of the most hazardous sections of road in the region. The danger is not from difficult terrain; it is from the deer and elk that have been dying there for decades.

A Highway That Has Been Killing Wildlife for Years

The numbers behind this project are stark. Between 2015 and 2020, more than 50 deer and 16 elk were recorded killed in vehicle collisions along the project corridor, the highest wildlife-vehicle conflict rate in the entire Caltrans District 2 region, which covers a large portion of Northern California. Those are the recorded fatalities. Unreported collisions are typically far more frequent.

U.S. 97 runs through a landscape that deer and elk have been moving across for thousands of years. The highway cut across those migration routes without accommodation for decades. Drivers hitting large animals at highway speeds face serious crash risks, and the burden on both wildlife populations and road safety accumulated year after year with no structural solution in place.

The $15.1 million crossing is the result. Caltrans District 2 describes the project as located on U.S. 97 from approximately 1.4 miles north of Deer Mountain Road to 0.6 miles north of the Grass Lake Rest Area, a roughly four-mile corridor where the new infrastructure will fundamentally change how animals and traffic coexist.

What the Bridge Is Built to Do

The overpass itself is approximately 100 feet long and 140 feet wide, wide enough that animals moving across it are not channeled through a narrow corridor but instead experience something closer to natural terrain. Width matters significantly in wildlife crossing design: crossings that are too narrow tend to be avoided by many species, particularly large ungulates like elk that are sensitive to confinement.

The bridge is paired with nearly two miles of eight-foot wildlife exclusion fencing running along both sides of the highway. That fencing is critical to the design. Without it, animals can still reach and cross the road at unprotected points, undermining the purpose of the overpass. The project also includes jump-outs positioned every half mile within the fenced corridor, which allow animals that wander onto the roadway to exit safely without becoming trapped.

The early adoption by the three deer is encouraging, but it is the elk population the project is most urgently designed to protect. Elk are large enough that collisions with them cause severe vehicle damage and can be fatal for drivers as well as animals.

A Second Structure and a Broader Push

About a mile down the same highway, a separate wildlife tunnel is also under construction as part of the same effort. The reinforced concrete culvert will provide an undercrossing option, expanding connectivity for smaller species and animals less likely to use an elevated overpass. Together, the bridge and tunnel represent a more complete solution than either structure alone.

Additional crossings may follow in the region. Caltrans District 2 has told reporters that two local groups are developing proposals for similar projects, one near Susanville on U.S. 395 and another on Interstate 5. Neither has received formal approval yet, but the success of the U.S. 97 crossing, even before completion, strengthens the case for expanding the network.

The Larger Picture for California Wildlife Crossings

Northern California is not the only part of the state pushing this kind of infrastructure. In Agoura Hills, about 30 miles northwest of Los Angeles, the Wallis Annenberg Wildlife Crossing is nearing completion over the 101 Freeway. Spanning 10 lanes of one of the nation’s busiest highways, the project will have a combined bridge footprint of nearly 56,000 square feet and is expected to become the world’s largest wildlife crossing when it opens in December 2026. At $114 million, it addresses the same fundamental problem as the Siskiyou crossing: urban development and highways have fragmented habitat, and species like mountain lions, coyotes, and deer need safe corridors to move, breed, and survive.

Both projects represent a shift in how highway infrastructure is designed and funded in California. Wildlife crossings were once considered an occasional special project; they are increasingly being treated as a standard component of responsible highway management. The same ecological pressures reshaping where species live, as seen with the westward spread of the fox tapeworm into Pacific Northwest wildlife populations, are also accelerating the case for infrastructure that keeps wildlife corridors intact.

The deer and bobcat that walked across the unfinished bridge in Siskiyou County did not wait for a ribbon-cutting. They found the safest path available and used it.

California’s wildlife bridges are working — and the animals found them first. Share this story and stay connected to what’s changing in the natural world with Weather Forecast Now.