View from St. Joseph's Hill Preserve of highway and dam infrastructure that limits human and wildlife movement / photo by Aaron Peth

Highway 17 Wildlife and Trail Crossings

View from St. Joseph's Hill Preserve of highway and dam infrastructure that limits human and wildlife movement (Aaron Peth)

Highways connect us, but also divide the land and create barriers to safe passage for both wildlife and people. In the Santa Cruz Mountains, California state highway 17 (Highway 17) fragments thousands of acres of open space, limiting the ability of wildlife to find food, mates and habitat, as well as preventing the completion of several regional trail systems. Together with private and public partners, neighbors and District constituents, Midpen is exploring the feasibility of developing two independent road crossings - a wildlife undercrossing and recreational trail overcrossing - to link over 30,000 acres of protected public lands.

The project also includes directional fencing that will help animals safely find their way to the wildlife crossing and a number of regional trail connections that will link the following Santa Clara County parks and Midpen open space preserves together across Highway 17: Sanborn County Park, El Sereno Preserve, Lexington Reservoir County Park, St. Joseph's Hill Preserve, Sierra Azul Preserve and Almaden Quicksilver County Park.

Natural Resources Protection and Restoration
Natural Resources
Public Access, Education, and Outreach
Public Access
Grant Funded
Grant Funded
illustration of a bird in flight next to the letters MAA
Measure AA
View of project site from El Sereno Preserve looking towards St. Joseph's Hill and Sierra Azul preserves / photo by Aaron Peth


  • Link over 30,000 acres of habitat and protected public lands on both sides of Highway 17, including Midpen preserves (El Sereno, St Joseph's Hill and Sierra Azul) and Santa Clara County Parks (Lexington, Sanborn and Almaden Quicksilver)
  • Improve motorist safety by reducing the potential for collisions with wildlife
  • Maintain healthy wildlife populations
  • Provide two structures - one for wildlife and one for recreational trail users - that support safe movement across Highway 17
  • Connect over 50 miles of existing regional trails, including Bay Area Ridge Trail, Juan Bautista De Anza National Historic Trail and Los Gatos Creek Trail

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View of Highway 17 in project area, looking north

While wildlife and trail crossings share similar goals, animals and people have unique needs and use crossings in different ways. To meet the requirements of both, two distinct and separate structures have been recommended to cross Highway 17: a wildlife undercrossing and a trail overcrossing. Two locations for each crossing structure are currently under environmental review:

  • a wildlife undercrossing either at Ravine Culvert (1) or Trout Creek (2)
  • a trail overcrossing either south of Trout Creek Canyon (3a) or north of Trout Creek Canyon (5a)
Highway 17 Project Overview map
Funded by Measure AA 2014 Open Space Bond

Mosaic of support

The Highway 17 crossings project, including regional trail connections and wildlife directional fencing, was identified as a Top 25 priority in Midpen's 2014 Vision Plan. As a result, $16 million of voter-approved Measure AA funds are allocated to partially fund the project. As the project is currently estimated to cost $40 million, Midpen collaborating with many partners and stakeholders to fund this work, including Senator Jim Beall, who facilitated a $5 million grant from the California Wildlife Conservation Board, and Senator Dave Cortese, who secured $2 million in the Budget Act of 2021.
2016 - 2018Feasibility study and revised alternatives report
2018 - 2019Caltrans Project Study Report
Regional Trails Connection Study
2020 - 2023Environmental review and Caltrans Project Report
Current status: Midpen preparation of Project Approval and Environmental Document (PA&ED) underway
2022 - 2025Design (plans and specifications)
2025 and beyondConstruction (funding dependent)