They will dig pretty deep. We considered getting some lengths of rebar (2-3 feet) or something similar and pounding them in around the foundation at 4” intervals, but that seemed like a huge amount of work and not guaranteed to work. Groundhogs are pretty strong and would probably find a way to move the spikes or even dig under them.
The problem we had was that there were litters of them born beneath our porch that were imprinted with the “smell of home”, so as soon as we dealt with one, we’d get a sibling taking over. You got to deal with all the generations that think your home is theirs. That can take a while, but in two years we haven’t had trouble.
BTW, we are in a housing development - not rural - so you can have problems anywhere.
Groundhog, the other-other white meat! I found a few recipes:
http://www.wildliferecipes.net/Game_recipes/Small_game_recipes/Woodchuck_recipes/index.asp
http://www.outdoor-michigan.com/Recipes/woodchuck_recipes.htm
http://www.motherearthnews.com/real-food/groundhog-day-groundhog-recipes.aspx