Groundhog burrow systems typically stretch 12 to 45 feet in total tunnel length, though some sprawling networks reach over 60 feet. Depth varies by purpose and season, but most tunnels run 2 to 5 feet below the surface, with hibernation chambers sometimes dug as deep as 6 feet. These numbers surprise people who picture a simple hole in the ground, because a single groundhog’s home is actually a multi-chambered, multi-entrance underground complex with distinct rooms for sleeping, hibernating, and even waste.
What a Typical Burrow System Looks Like
A groundhog burrow is not a single straight tube. It branches. The main tunnel descends from the entrance at a steep angle for the first foot or two, then levels off into a roughly horizontal passage that weaves through the soil at a depth of about 2 to 4 feet. Off this main corridor, short side tunnels lead to separate chambers. There is usually a nesting chamber lined with dried grass and leaves, a hibernation chamber set deeper in the system, and at least one latrine area where the groundhog deposits waste away from its living quarters.
The total length of tunnels in a single burrow system averages somewhere between 12 and 45 feet, but well-established burrows used across multiple years can grow considerably longer. A groundhog that has lived in the same spot for several seasons may extend existing passages, add new chambers, or connect previously separate tunnel sections. It is not unusual for older burrow complexes in loose, well-drained soil to exceed 50 feet of combined tunnel length. The diameter of the tunnels themselves is generally 6 to 8 inches across, just wide enough for the animal to move comfortably.
How Deep the Tunnels Actually Go
Most of the horizontal tunnel network sits between 2 and 5 feet underground. The entrance tunnel drops steeply at first, sometimes descending 2 to 3 feet within just the first few feet of horizontal distance, before flattening out. This initial plunge makes the burrow harder for predators to flood or reach into.
The deepest parts of the system tend to be the hibernation chambers. Groundhogs hibernate from roughly October through February in much of their range, and the chamber where they spend those months is typically set at the lowest point in the burrow, sometimes 5 to 6 feet down. At that depth, soil temperatures stay more stable through winter, insulating the hibernating animal from the worst surface cold. The nesting chamber used during warmer months is often shallower, sitting closer to 2 or 3 feet below grade.
Soil type matters a lot. In sandy or loamy soils that are easy to dig, groundhogs can excavate deeper and longer systems with less effort. Heavy clay soils or areas with a high water table limit how deep and how far the tunnels extend. Rocky terrain forces tunnels to follow the path of least resistance around obstructions, sometimes resulting in shallower, more winding networks.
Multiple Entrances and Escape Routes
A typical groundhog burrow has two to five entrances. The main entrance is the easiest one to spot because it has a conspicuous mound of excavated dirt, sometimes a foot or more high and several feet across. This is the pile of soil the groundhog kicked out while digging. The groundhog often uses this mound as a lookout post, sitting upright on it to scan for predators.
The other entrances are usually less obvious. These are often called “plunge holes” because they drop straight down into the tunnel system without any telltale dirt mound. The groundhog pushes excavated soil out through the main entrance, so the plunge holes stay relatively clean and hidden in grass or brush. Their purpose is escape. A groundhog foraging 20 or 30 feet from its main entrance can dive into a nearby plunge hole and be underground in seconds if a hawk, fox, or dog approaches.
The spacing of these entrances gives you a rough sense of how far the tunnel system extends horizontally. If you find one entrance near a garden shed and another 30 feet away along a fence line, the tunnel connecting them runs at least that distance underground, with likely a few extra feet of branching passages to chambers along the way.
Summer Burrows Versus Winter Burrows
Groundhogs sometimes maintain separate burrow systems for different seasons, which is a detail that catches many homeowners off guard. The summer burrow is typically located near food sources: the edge of a field, a vegetable garden, or a meadow with clover and dandelions. These burrows tend to be shallower and may be less elaborately chambered, since the groundhog is spending most of its time above ground eating and fattening up.
The winter burrow, where the groundhog will hibernate, is often in a different location entirely, frequently in a more sheltered spot like a wooded area or a hillside. Winter burrows tend to be dug deeper, with the hibernation chamber positioned well below the frost line. In northern parts of the groundhog’s range, where frost can penetrate 3 or 4 feet into the soil, the hibernation chamber may sit 5 to 6 feet down. The groundhog plugs the entrance from inside with soil before settling in for the winter, which helps regulate temperature and humidity and keeps predators from wandering in.
Not every groundhog maintains two separate burrows. Some use a single system year-round, especially if the location offers both food access and suitable depth for hibernation. But the distinction explains why you might see a groundhog abandon a burrow in autumn and show up in a completely different part of your property the following spring.
How Much Soil a Groundhog Moves
The sheer volume of earth a groundhog displaces is striking for an animal that weighs only 5 to 14 pounds. Estimates based on burrow dimensions suggest that a single groundhog excavates roughly 35 cubic feet of soil over the life of a typical burrow system, which translates to several hundred pounds of dirt. Over a lifetime, a groundhog that digs multiple burrows can turn over more than 700 pounds of subsoil.
This excavation has real ecological value. Burrowing vertebrates decrease soil bulk density and increase infiltration rates, porosity, and permeability, and they introduce organic matter, nitrogen, and potassium into the soil through deposited excrement and dragged-in plant material.1Soil Science. Burrowing Through the Literature: The Impact of Soil-Disturbing Vertebrates on Physical and Chemical Properties of Soil The soil that gets pushed to the surface from deep underground brings buried minerals into the topsoil layer. This mixing, combined with the aeration that open tunnels provide, improves water balance and creates microsites where seeds can germinate and establish more easily.2Ecological Management & Restoration. The role of small ground‐foraging mammals in topsoil health and biodiversity: Implications to management and restoration
Abandoned groundhog burrows also become homes for other wildlife. Foxes, skunks, opossums, rabbits, and various snake species all use old groundhog tunnels as shelter. In regions where these animals lack the ability to dig their own dens, groundhog burrows are a critical housing resource. The ecological role of the groundhog as an “ecosystem engineer” is often underappreciated precisely because most of its work happens out of sight.
The Damage They Can Cause
The same tunneling ability that benefits soil ecology can create serious problems for human structures. Burrows dug near or under foundations, patios, retaining walls, and sheds can undermine structural support as the tunnels shift soil and create voids. Settling and cracking in concrete are common consequences when a burrow system runs beneath a slab.
Agricultural equipment is vulnerable too. A tractor wheel dropping into a collapsed burrow entrance in a field can damage the equipment or injure the operator. The risk is particularly acute at equestrian facilities, where a horse stepping through the thin soil ceiling of a tunnel can break a leg, with severe consequences for both horse and rider.3Journal of Environmental and Engineering Geophysics. Case Histories of Gpr For Animal Burrows Mapping and Geometry This hazard is insidious because the tunnel may be invisible from the surface until the moment of collapse.
Groundhog burrows can also redirect water flow underground in ways that cause erosion. If a burrow system channels rainwater beneath a driveway or along a foundation, it can wash out supporting soil over time. Levees and earthen dams are particularly sensitive to this kind of undermining, and wildlife managers in some regions actively monitor for groundhog activity near flood-control structures.
How to Tell If You Have a Groundhog Burrow
The most obvious sign is the main entrance hole, typically 10 to 12 inches in diameter, with a fan-shaped mound of freshly turned dirt in front of it. The soil in the mound is often a different color than the surrounding topsoil because it has been brought up from a deeper layer. If the mound looks recently disturbed and the hole shows no cobwebs or leaf litter, the burrow is probably active.
Plunge holes are harder to find. Look for secondary openings without dirt mounds, roughly the same diameter, often partially hidden under brush, decks, or rock piles. The grass around a plunge hole may be worn down from repeated use. In winter, you can sometimes spot active burrows by watching for holes that remain clear of snow, warmed slightly by the animal’s body heat below.
Other clues include gnaw marks on wooden structures near the suspected burrow, well-worn paths through grass between the burrow entrance and a food source, and characteristic droppings, which are oblong and usually deposited in the latrine chamber underground rather than on the surface. Groundhog tracks show four toes on the front feet and five on the rear, though in practice, tracks are less reliable than finding the burrow entrance itself.
What Determines the Size of a Burrow System
Several factors control how expansive a particular groundhog’s tunnel network becomes. Age is a big one. A young groundhog establishing its first burrow in spring may dig only a simple tunnel with one chamber and one or two entrances. A mature adult that has occupied a site for years will have expanded and renovated the system repeatedly, adding passages and chambers that can make the total network considerably longer and more complex than average.
Soil conditions are another major factor. Groundhogs prefer well-drained soils and tend to choose sloped ground or raised areas where water will not flood the tunnels. In ideal digging conditions, tunnel systems grow more elaborate. In heavy clay or gravelly soils, the animal expends more energy per foot of tunnel and the resulting system tends to be shorter and shallower.
Population density also plays a role. Where groundhogs are abundant and territories are small, burrow systems may overlap or sit close together, and individual burrows tend to be less sprawling. In areas with lower groundhog density, a single animal may range more widely and maintain a larger or more distributed set of tunnels. Females with litters sometimes expand the nesting chamber and add extra escape routes, producing a temporarily more complex system during the breeding season.
Getting Groundhogs to Leave Without Destroying the Burrow
If you have a groundhog burrow where you do not want one, the first question worth asking is whether it actually needs to go. A burrow in the back corner of a large property, well away from foundations and gardens, is doing useful ecological work and hosting an animal that is largely minding its own business. But if the burrow is under your porch, next to your foundation, or in a horse pasture, action is warranted.
Exclusion is generally more effective than lethal control. One common approach is to install an L-shaped wire mesh barrier around the area you want to protect, burying the horizontal foot of the L about 12 inches deep so the groundhog cannot dig under it. Hardware cloth with half-inch openings works well. For burrows near structures, you can wait until the groundhog leaves to forage during the day, then loosely stuff the entrance with newspaper or leaves. If the stuffing remains undisturbed for three to five days, the burrow is likely vacant and you can fill it with compacted soil and gravel.
Filling an active burrow without first evicting the occupant is both inhumane and ineffective. Groundhogs are strong diggers and will simply re-excavate a filled tunnel or open a new entrance nearby. Harassment techniques like placing ammonia-soaked rags near the entrance, running a garden hose into the tunnel to create an uncomfortable environment, or installing a one-way exclusion door can encourage the animal to relocate on its own. In areas where local regulations allow it, live trapping and relocation is another option, though relocated groundhogs have mixed survival rates and you should check state and local wildlife laws before attempting it.
When Professional Assessment Makes Sense
For burrows near building foundations, retaining walls, or earthen structures like dams or levees, a visual inspection from the surface may not tell you enough. The tunnel network underground could be far more extensive than the entrance locations suggest. Ground-penetrating radar (GPR) has been used to map animal burrow systems without excavation, revealing tunnel paths, chamber locations, and the proximity of voids to structural footings.3Journal of Environmental and Engineering Geophysics. Case Histories of Gpr For Animal Burrows Mapping and Geometry This kind of survey is not something most homeowners will pursue, but it is worth knowing about if you are dealing with potential structural undermining or managing a property where animal burrows pose safety risks, such as horse farms or flood-control earthworks.
A licensed wildlife control operator can assess the situation, identify all visible entrances, and recommend whether exclusion, trapping, or structural repair is the right path. In most cases, the combination of evicting the groundhog, filling the burrow properly with tamped soil and gravel, and installing exclusion fencing to prevent re-colonization resolves the problem without recurring issues. The tunnels themselves, once vacated and filled, compact over time and generally do not cause ongoing settling if the fill is done correctly.