How deep?
It is not unusual for a groundhog to tunnel down ten feet or more.
Does your garage have a basement under it? If it doesn’t (most garages are built on a slab with a base less than three feet in the ground) a groundhog will find it a prime place to build a home.
If you want to discourage such a home maker you can bury chicken wire (stainless steel for long term) about three to five inches under ground horizontally next to your foundation. The groundhog will begin digging hit the chicken wire and not be able to dig through it and move on.
The garage and house have a 2000 sq. ft. basement. The “exterior” walls of the basement are made of cinder block. They are faced with brick in the “walk-out” portion.
There are no groundhog holes anywhere near the house (we check). But I like your chicken wire idea for the ground in front of the walk-out part.
At the place we rented before we bought this one, we had a groundhog living under the garage. There wasn’t much dirt outside his hole, so we thought nothing of it - ignorant former tract-home dwellers from California.
I’m positive that if the landlord saw the hole to its burrow after we moved out, that groundhog is deceased and the hole is full of concrete. He had no problem killing vermin, and he isn’t nearly so ignorant as we were.