Safe Passage – Interstate 5
Reconnecting the Cascades and Olympic Peninsula through science-based wildlife crossings and protected habitat corridors across Interstate 5.
Our Approach
Advancing wildlife crossings that reconnect the Cascades and the Olympic Peninsula across the I 5 barrier.
Southwest Washington holds the last viable pathways linking these two mountain ranges, but rapid development and heavy traffic have nearly closed them off. Our collaborative effort identifies, studies, and prepares priority crossing locations so they are shovel ready and competitive for major infrastructure funding. By grounding the work in genetics, hydrology, habitat modeling, and Tribal and community partnerships, we are securing the corridor that species like elk, cougar, fisher, and salmon need to move, adapt, and survive in a changing climate.
Current Focus
Work We’re Doing to Achieve Safe Passage - Interstate 5 Goals
Safe Passage Planning
We are advancing Safe Passage I-5 through a coordinated, science-driven effort to reconnect wildlife habitat between the Cascade Mountains and the Olympic Peninsula.
Working with WSDOT, WDFW, Tribal partners, and regional stakeholders, we helped complete feasibility analyses identifying the most promising locations for future wildlife crossings along Interstate 5. These studies evaluate engineering constraints, habitat suitability, and cost considerations, providing the technical foundation to move the project toward implementation.
A core component of our work is securing and protecting key habitat parcels that anchor the two remaining viable linkage zones.
Corridor Protection
Through the Cascades to Olympics capital campaign, we are acquiring and stabilizing lands from conservation-driven landowners in priority corridors to ensure long-term wildlife movement.
Impact & Results
A History of Safe Passage - Interstate 5
Interstate 5 is a major barrier between the Cascade Mountains and the Olympic Peninsula, fragmenting key ecosystems and limiting wildlife movement. Increasing development and traffic make restoring connectivity increasingly urgent.
Interstate 5 is a major barrier between two of Washington’s most important ecosystems.
A wide range of species depend on connected habitat across the Southwest Washington lowlands.
Rapid development is closing the window for effective crossing infrastructure.
Interstate 5 is a major barrier between two of Washington’s most important ecosystems.
The I-5 corridor disrupts ecological connectivity between the Cascade Mountains and the Olympic Peninsula, fragmenting habitat and limiting wildlife movement across southwest Washington. This break in connectivity affects some of the most biodiverse landscapes in the state.
A wide range of species depend on connected habitat across the Southwest Washington lowlands.
Roosevelt and Rocky Mountain elk, cougar, black tailed deer, black bear, fisher, and western gray squirrel all rely on the ability to move across the landscape for seasonal foraging, dispersal, and long term population resilience. Tens of thousands of vehicles travel I-5 each day, creating a significant barrier and increasing wildlife vehicle collision risk.
Rapid development is closing the window for effective crossing infrastructure.
Industrial growth and new infrastructure from the Chehalis Basin to the Columbia River are narrowing the last viable locations for wildlife crossings. Without proactive planning and protection, key linkage zones could be lost, making it far more difficult to restore connectivity between the Cascades and the Olympics.
Impact & Results
Our Key Accomplishments for Safe Passage - Interstate 5
From protecting critical landscapes to advancing collaborative forest restoration, these efforts deliver lasting benefits for wildlife, habitat connectivity, and climate resilience.
Phase One Planning
Securing Initial Funding for Science-Based Wildlife Crossing Design
Obtained initial funding to begin Phase One planning for wildlife crossings, supporting analysis of development trends, land use change, and corridor protection needs across southwest Washington. This work is laying the foundation for engineering studies, wildlife monitoring, and design development to make priority crossing sites shovel ready for state and federal infrastructure investment.
Priority Connectivity Zones
Identifying Key Linkages for Cascades–Olympics Wildlife Movement
Interstate 5 News
stay Connected
Additional Resources
Media & Archive Resources