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Wallis Annenberg Wildlife Crossing Aims To Link Mountain Habitats

lite News Desk 2 min read

At a glance

  • Wildlife crossing under construction over U.S. 101 in Agoura Hills
  • Project began in April 2022, expected to finish by fall 2026
  • Designed to connect Simi Hills and Santa Monica Mountains

The Wallis Annenberg Wildlife Crossing is being built to provide a safe passage for animals over U.S. Route 101 at Liberty Canyon, connecting two key mountain habitats in California.

Construction on the vegetated overpass started in spring 2022 after a groundbreaking event held on Earth Day. The project is located in Agoura Hills and is intended to link the Simi Hills with the Santa Monica Mountains, supporting wildlife movement between these areas.

The completed crossing will measure about 200 feet long and 165 feet wide, which would make it the largest wildlife overpass globally. The design includes vegetation to blend with the surrounding landscape and encourage use by native species.

Funding for the project comes from both private and public sources. Initially, private donations made up around 60% of the total, but in February 2026, Governor Newsom announced an additional $18 million in state funding, shifting the balance to approximately 40% private and 60% public support.

What the numbers show

  • Construction began on April 22, 2022
  • Completion is expected by fall 2026
  • The overpass will be 200 feet long and 165 feet wide
  • At least 12 mountain lions have died on U.S. 101 since 2002
  • Public funding increased to 60% after 2026 state allocation

Wildlife tracking data shows that most mountain lions approach the freeway and turn back, with only a few successfully crossing. Since 2002, at least a dozen mountain lions have been killed on this stretch of highway, highlighting the need for a dedicated crossing.

Genetic studies conducted by the National Park Service indicate that the isolated mountain lion population in the Santa Monica Mountains requires more frequent crossings to maintain genetic diversity. Currently, a new lion crosses the freeway about once every 12 years, but scientists estimate that crossings should occur every two to three years to prevent genetic collapse.

There have been rare instances of successful crossings. In 2017, a young male mountain lion known as P-55 crossed U.S. 101 and nearby highways, as confirmed by GPS tracking. In 2018, another mountain lion, P-64, used a culvert near Liberty Canyon to cross the freeway multiple times, becoming one of only five known to have made the journey and the second to enter the Santa Monica Mountains.

Completion of the Wallis Annenberg Wildlife Crossing is anticipated by fall 2026, with the aim of improving safe passage for wildlife and supporting the long-term health of mountain lion populations in the region.

* This article is based on publicly available information at the time of writing.

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