The Wallis Annenberg Wildlife Crossing will span U.S. Highway 101 to connect the Santa Monica Mountains along the Pacific Ocean with the Sierra Madre Range to the north. (Rock Design Associates and National Wildlife Federation)
The largest wildlife crossing in the world completed its first phase in June 2025, paving the way for restored ecosystem connectivity in the Los Angeles area. Sited among challenging terrain and over one of the busiest highways in the country, the Wallis Annenberg Wildlife Crossing will span 210 feet across U.S. Highway 101 in Agoura Hills, Calif., linking the Santa Monica Mountains and the Sierra Madre Range with a 174-foot-wide living bridge, roughly equivalent in width to six lanes of roadway.
Led by a team with representatives from the National Wildlife Federation (NWF), the California Department of Transportation (Caltrans), the National Park Service (NPS), the Santa Monica Mountains Conservancy and the Mountains Recreation & Conservation Authority, the project’s first phase involved construction of the vegetated superstructure. Its second and final stage—now underway and scheduled to complete at the end of 2026—includes the relocation of utility lines, earthwork and restoration of wildlife habitat adjacent to U.S. 101…