I have the same problem frequently. I would cover the entrance with chicken wire and cinder block and they would dig at another spot the next year.
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Had groundhogs digging into my pole barn like that. I trapped the user, and he joined my swim team, so I knew he wasn’t around anymore and filled the entrance with gravel.
Next year at the exact same spot, a new hole appeared. He was living in my barn. He actually had another hole inside my barn under some pallets. He too, became a member of my swim team.
Filled the area with quik crete and nothing digs there anymore. They can become very persistent at digging into areas you don’t want them. I think the local coyotes are keeping the population in check now.
Good luck
I have a groundhog living on and off under my shed as well. I do not see it on a regular basis. I believe it lives under my shed during the winter. However, this year I had quite a surprise. The groundhog had 5 babies!!! As the months went on I would see less and less of them. I only see what I think is maybe one or two of them now. One I’ve seen up at the front of my property and rummaging through my orchard eating the apples drops. The other one I see ( maybe the same one, I am not sure) comes out from under the shed to eat grass out in front of the shed. The 5th baby groundhog was shy and start to the right of the ramp and shed in the behind my plants. Coming out off and on during the time I was trying to take the photos.
Trapping woodchucks (they don’t look like big pigs!) is an essential tool of gardeners in my region. When you know where they sleep it’s pretty easy- they tend to enter the world of light groggily and will wander right into a live trap right in front of the entrance to their burrow- a neighbor gardener tells me, even without bait. I always use bait… apples will do.
I used to be willing to share some fruit with them, but once they began violating my veg garden fence it was curtains for them. I’m not sure relocating them does them any favors over providing them with a quick death after capture…just check the trap frequently, they suffer greatly in incarceration, unlike, say, skunks.
When I can’t locate their burrows and one starts raiding my garden, I have to cover all the food they like with floating row covers until they enter a trap I set between rows of their favorite food. That’s a trick I learned from that previously mentioned neighbor who is about 10 years my senior and lived and gardened in this region his entire life (well, he didn’t start gardening immediately).
Be careful. When I find burrows like that it’s 50/50 groundhog or skunk.
I found that a lot of groundhog holes are security shelters. Some where they can dive into when danger comes around. They were eating my pumpkin plants row by row.
I guarded several holes with Conibear traps for days only to get results every 3-4 days multiple times. All at different times. I took 27 groundhogs out of that 7 acre field.
Often live traps with something drapped over it to make it appear like a tunnel is too much for them to resist, bait or no bait they walk into it.
I am going the conibear trap route. I’ve tired all sort of traps, but never these.
Just be careful. They work, but also will work on your pets or neighbors pets. There is no turning them loose. I don’t use them anymore for that fear.
The larger ones 220-s and up, are often illegal to set on land, and are meant for water sets for beaver.
I suspect you have a predator shortage there. We have groundhogs, but they are mostly a walking bologne sandwhich for a coyote. Our owls even eat skunks. Now, what i never want to find in a burrow is a badger. They can hold their own. I cut a wide path around them when i can. I have encountered a badger when i was sick and couldnt run. The badger gave me a free pass. Those ground hogs must have some natural enemies there even if it is a borrowed dog if you dont have your own.
Badgers have stripes for a reason.