I just found out two nights ago who it is that lives under my shed! Yes, it is a groundhog. Probably a pretty happy one, because he/she has about four or five entrance holes.
Any garden damage, I have chalked up to the deer, because things tend to be munched at least 12" off the ground.
Do you think this groundhog would be responsible for the holes in my lawn, probably about 100' away from the shed? We had an ancient - and huge - cottonwood poplar tree which we had taken down quite a number of years ago. And the roots are still rotting out, and where they were the lawn is just chock full of holes. But I never see the critter(s) who have done the excavating.