I presume you want live capture? Use humane trap with suitable bait near burrow. Spring loaded door. Follow the County regulations :-)

Hi Andrew,

For ground squirrels, I prefer Tomahawk traps. They are rugged, easy to set/bait and fairly light weight. If you are backpacking the traps in to your site, tomahawk makes a collapsible version of most of their trap sizes. The size that I suggest for your species is the 103 listed on the Tomahawk website. This is the size I have used for 13-line GS's. I use the 603 series for arctic GS's.  Having a trap that is a little large for your species is not a problem. However, obviously, a too small trap is problematic. 

Good luck and happy trapping!

Loren

I also prefer Tomahawk traps.  Just make sure to check the ends of the wires - sometimes they can be pretty sharp, and can injure little paws as they try to dig around the trap.  A flat file can be used to take off the sharp edges.  Too large a trap can be a problem if the mesh size is big enough to get their nose through.

Hi Kendall. Same here, we have been using Tomahawk live traps for over 25 years on Columbian ground squirrels. Successful and humane.