Groundhogs in the yard: why the burrow, not the animal, is the problem
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By John Stopka, Co-Founder & CEO · Reviewed by John Stopka
A groundhog in the vegetable patch is an annoyance. The burrow under the shed is the real problem. University of Kentucky puts a woodchuck burrow system at up to 5 feet deep and 25 to 30 feet long, with at least two entrances [1] — and some of them are dug from below ground, with no mound of dirt to give them away [1]. Filling in the one hole you can see settles nothing.
How big is a groundhog burrow?
Far bigger than the hole in the lawn suggests.
University of Kentucky's wildlife publication says burrow systems "may be 5 feet deep and 25 to 30 feet in total length", and that they "are extensive and each system has at least two entrances" [1].
The main entrance is the obvious one: a mound of excavated dirt beside a 10- to 12-inch diameter hole [1]. The rest are not. Secondary entrances "may be hard to identify because they are dug from below ground and do not have mounds of dirt beside them", and they "often serve as escape holes" [1]. Illinois Extension calls these plunge holes, dug from the inside, so there is no mound [3].
One hole beside a shed is a doorway, not the room.
Why doesn't filling in the hole do anything?
Because you have shut one door in a structure with several.
The animal is still underneath, and it does not need to go far. Woodchucks "usually do not range more than 50 to 100 feet from the den", and most of their activity is concentrated around the burrows [1].
University of Kentucky's own control procedure starts by locating every entrance around an active burrow, lists "inadequate plugging of all burrow entrances" among the factors that decide whether burrow treatment succeeds, and ends by going back two or three days later to see whether the burrow has been reopened [1].
The work is aimed at the whole system. The visible opening is the least of it.
How can you tell whether a burrow is active?
Look at the soil, then look at the calendar.
A fresh mound of excavated dirt beside a 10- to 12-inch hole is the mark of a main entrance in use [1]. The unmounded openings nearby belong to the same system, not to a second problem [1].
Season matters as much, because groundhogs do not keep one burrow all year. Illinois Extension describes a single-entry winter burrow dug in woodland under tree roots; when the animals come out, they "move into more open areas to live closer to food sources and will dig new more elaborate burrows leaving their winter bed behind" [3].
A burrow they have left does not stay empty either — University of Kentucky notes that in late summer, fall and winter "other game animals may use the burrows for protection" [1]. An empty-looking hole is a question, not an answer.
Does the problem go away over winter?
No. It goes quiet.
Hibernation "usually begins in October and continues through February" [1]. Just before it, in late August and September, woodchucks "have voracious appetites as they prepare to hibernate" [1]. Then it restarts: males emerge first, breeding happens in March, and four to five young are born in April [1].
That is the trap in the seasonal rhythm. The yard goes still in October, the digging stops, the burrow looks finished — and nothing has been resolved.
University of Kentucky is direct about the timing: "Control is most effective in the spring, when active burrows are easily located, young woodchucks have not yet scattered, and there is less likelihood of damage to other wildlife" [1].
What can a homeowner legally do about a groundhog?
Less than most people assume, and it differs by state.
In Kentucky, groundhogs are a hunted species: the Department of Fish and Wildlife Resources says they "may be hunted statewide, year-round, with no bag limit", and that a hunting license is required unless the hunter is license exempt [2]. That is a rural answer, not a suburban one.
In Illinois, Illinois Extension is explicit: if you need to remove the animal, "trapping is the suggested method and you must get a permit from the Illinois Department of Natural Resources or call a nuisance wildlife control operator" [3].
University of Kentucky says no poisons are registered for controlling woodchucks in Kentucky, and warns against putting a burrow fumigant under homes, sheds or other buildings because of the fire hazard [1]. Near buildings, it says, trapping "is the best method" [1] — which is exactly where a burrow under a deck or porch leaves you.
How does Liberty handle groundhogs?
Groundhogs aren't part of our pest control plans. Wildlife control starts with a free wildlife inspection.
A local Service Advisor does a thorough inspection to see how bad the problem is, where groundhogs are burrowing, like next to foundations, sheds and decks, and what draws them, like gardens and sheltered spots to dig.
When needed, we trap and remove groundhogs from burrows near your home, shed or deck. We close off burrow entrances and block the spaces under decks, porches and sheds where groundhogs dig.
After the groundhogs are out, we come back to check for new burrows and check that the closed-off areas are holding.
Wildlife control and Liberty Home Services, which covers exclusion products, cover the Paducah area, Southern Illinois and the Hopkinsville area — not the Bowling Green area.
When to call a professional
Call when a burrow entrance sits against a foundation, slab, shed, deck or porch, when there is more than one opening in the yard, or when a hole you filled in has been reopened.
The inspection settles which openings belong to one system, whether it is in use, and what is keeping the animal there. That is why groundhogs sit under wildlife control rather than a pest control plan.
Common questions
How do I know if a groundhog burrow is still active?
Start with the main entrance: a 10- to 12-inch hole with a fresh mound of excavated dirt beside it is a burrow in use [1]. Groundhogs also shift between a woodland winter burrow and a more elaborate summer one [3], so a quiet opening may be the wrong burrow to watch — and one they have truly left is often taken over by other animals [1].
Will a groundhog burrow damage my foundation?
Groundhog burrows can loosen the soil next to foundations, slabs, sheds and decks. A burrow may also have more than one entrance, sometimes several feet away. University of Kentucky records that woodchucks burrow around building foundations, and that their holes and mounds create hazards for livestock, farm equipment and people [1]. How far it goes in a given yard is what the inspection is for.
Is a groundhog the same as a woodchuck?
Yes. Groundhogs and woodchucks are the same animal. University of Kentucky's publication uses woodchuck throughout and notes that the animal is often called a groundhog or a whistle pig [1].
Are groundhogs covered by a pest control plan?
No. Groundhogs aren't part of our pest control plans. They are handled through wildlife control, which starts with a free wildlife inspection, and that service is not offered in the Bowling Green area.
Sources
- University of Kentucky Cooperative Extension Service. Thomas G. Barnes. "Managing Woodchuck Problems in Kentucky" (FOR-44). https://publications.mgcafe.uky.edu/sites/publications.ca.uky.edu/files/for44.pdf (opens in a new tab)
- Kentucky Department of Fish and Wildlife Resources. "Other Species" (hunting seasons and special restrictions by species). https://fw.ky.gov/Hunt/Pages/Other-Hunting-Seasons.aspx (opens in a new tab)
- University of Illinois Extension. "Great groundhogs: Getting to know Illinois' burrowing hibernator" https://extension.illinois.edu/blogs/naturalist-news/2021-01-29-great-groundhogs-getting-know-illinois-burrowing-hibernator (opens in a new tab)