World’s Largest Wildlife Crossing Under Construction in Southern California

Progress has been made on construction of the Wallis Annenberg Wildlife Crossing over the 101 Freeway in Southern California, which is set to be the largest wildlife crossing of its kind in the world. The crossing will connect the Santa Monica Mountains and the Simi Hills, and will facilitate safe passage for wildlife over the busy freeway.

The bridge, located near the Liberty Canyon Road exit in Agoura Hills, is about 210 feet long and 174 feet wide, according to Caltrans (the California Department of Transportation). Lettering has recently gone up on the structure, reading “Annenberg Wildlife Crossing” facing both northbound and southbound traffic on the freeway.

Stage 1 of construction has focused on building the section over the 101 Freeway, while Stage 2 of construction will focus on a section over nearby Agoura Road, with both eventually creating a seamless crossing that blends with natural areas to the north and south of the freeway.

Caltrans estimates the total cost for the project will be $92 million. The project broke ground in the spring of 2022, with completion initially expected in 2025. After delays in construction due to heavy rains in 2022 and 2023, the crossing is now expected to be completed in 2026.

Watch video of the state of the crossing in June 2025 here: