California’s 27 mule deer herds span the Sierra Nevada, the Modoc Plateau, the Mendocino Range, the Klamath country and the southern Sierra. Pronghorn herds in the northeast — Bodie, Wassuk, Lassen, Clear Lake — are shared with Nevada. This map shows every USGS-mapped big-game migration corridor in California — 31 herd units, 989 GPS-collared animals, and 3,256 tracked migration segments, recorded between 1999 and 2024.

Click any corridor or stopover for herd-level stats. Toggle species on and off in the controls above the map, or pick a featured corridor lower on the page to load real GPS tracks onto the map.

Big-game migration in California by the numbers

• 31 mapped herd units
• 989 individual animals tracked by GPS collar
• 3,256 GPS migration tracks recorded between 1999 and 2024
• 33,527 km² of migration corridor identified
• 29 stopovers — critical rest and refuel sites along the corridors

Species tracked in California

• Mule Deer — 21 herd units mapped in California
• Pronghorn — 6 herd units mapped in California
• Elk — 4 herd units mapped in California

Every tracked herd unit in California

The complete list of USGS-mapped herd units that include California. Cross-border herds shared with neighbouring states are included.

• Elk: East Shasta herd — 18 tracked animals, 1999–2019
• Elk: Egg Lake herd — 11 tracked animals, 2001–2019
• Elk: Marble Mountain herd — 0 tracked animals, —
• Elk: West Goose Lake herd — 12 tracked animals, 1999–2020
• Mule Deer: Blue Canyon herd — 3 tracked animals, 2018–2019
• Mule Deer: Bucks Mountain Mooretown herd — 4 tracked animals, 2018–2020
• Mule Deer: Carson River herd — 47 tracked animals, 2012–2019
• Mule Deer: Casa Diablo herd — 112 tracked animals, 2014–2022
• Mule Deer: Downieville Nevada City herd — 8 tracked animals, 2018–2021
• Mule Deer: Doyle herd — 14 tracked animals, 2016–2019
• Mule Deer: East Tehama herd — 35 tracked animals, 2010–2018
• Mule Deer: East Walker herd — 101 tracked animals, 2017–2024
• Mule Deer: Grizzly Flat herd — 5 tracked animals, 2018–2021
• Mule Deer: Jawbone Ridge herd — 83 tracked animals, 2010–2015
• Mule Deer: Kern River herd — 27 tracked animals, 2020–2021
• Mule Deer: Loyalton herd — 31 tracked animals, 2006–2017
• Mule Deer: Manache herd — 39 tracked animals, 2020–2021
• Mule Deer: Mendocino herd — 50 tracked animals, 2004–2021
• Mule Deer: Modoc herd — 21 tracked animals, 1999–2020
• Mule Deer: Pacific herd — 43 tracked animals, 2015–2019
• Mule Deer: Salt Springs herd — 7 tracked animals, 2018–2020
• Mule Deer: Siskiyou herd — 67 tracked animals, 2015–2020
• Mule Deer: Upper San Joaquin herd — 30 tracked animals, 2013–2016
• Mule Deer: Verdi Truckee herd — 31 tracked animals, 2009–2017
• Mule Deer: West Walker herd — 129 tracked animals, 2017–2024
• Pronghorn: Bodie Wassuk herd — 18 tracked animals, 2014–2016
• Pronghorn: Clear Lake herd — 21 tracked animals, 2015–2020
• Pronghorn: Lassen herd — 7 tracked animals, 2015–2017
• Pronghorn: Likely Tables herd — 15 tracked animals, 2014–2020
• Pronghorn: Mount Dome herd — 0 tracked animals, —
• Pronghorn: Surprise Valley herd — 0 tracked animals, —

What threatens migration corridors in California

Across the West, the biggest threats to big-game migrations are not the things that kill individual animals — they’re the things that fragment the corridor itself. Energy development, road crossings, fences and subdivision of winter range have all been documented as drivers of corridor loss in this dataset. State wildlife agencies, the USGS Corridor Mapping Team, and conservation NGOs are now using maps like this one to guide decisions about where to build wildlife crossings, where to replace woven-wire fences, and where to prioritise conservation easements on private winter range.

Explore further

This page is part of MapScaping’s western big-game migration series. See the Western US Big Game Migration Map for the complete dataset across all ten states, or browse a different state:

• Arizona
• Colorado
• Idaho
• New Mexico
• Nevada
• Oregon
• Utah
• Washington
• Wyoming