Round holes in the ground are almost always made by animals, insects, or crustaceans, and the single best clue to identifying the culprit is the hole’s diameter. A quarter-inch opening points to solitary bees. A hole the size of a silver dollar suggests chipmunks. Knowing the size, the soil conditions, and whether there’s a dirt mound nearby will narrow the list fast.
Tiny Holes: Solitary Bees and Other Insects
The smallest round holes you’ll find in a lawn or garden, roughly 1/4 inch across, are typically made by mining bees. These are solitary, ground-nesting bees that dig individual tunnels in bare or thin soil, often in sunny spots. Each hole may be surrounded by a small mound of excavated dirt. Mining bees are not aggressive and rarely sting. They’re active in spring, and the holes usually disappear on their own within a few weeks as the bees finish nesting.
Cicada nymphs leave slightly larger holes, about 1/2 inch wide (roughly the size of a dime), when they emerge from the soil after years of underground development. These holes appear suddenly, sometimes by the hundreds, and you may see mud turrets around them that stand 2 to 3 inches tall. If you’re finding dime-sized holes in late spring or early summer with no ongoing activity, emerging cicadas are the likely explanation.
Half-Inch Holes: Spiders and Wasps
Burrowing wolf spiders dig holes roughly half an inch across, often in sandy or loose soil. Their tunnels have a more structured look than a random poke in the dirt because the spiders reinforce the upper walls with layers of silk. Some species even build a hinged door of silk and sand to seal the entrance during winter or when guarding eggs. You’ll typically find these holes in undisturbed areas: sandy paths, dune edges, or the margins of gardens.
Cicada killer wasps, which are large solitary wasps, create holes in a similar size range but usually kick out a noticeable fan-shaped pile of soil. Despite their intimidating size, these wasps are docile toward people.
One-Inch Holes: Voles
If the holes are about 1 inch in diameter, voles are a strong possibility, especially if you also see narrow trails worn through the grass. Meadow voles build surface runways (look for clipped grass and tiny droppings that resemble grains of rice), while pine voles stay mostly underground and leave small piles of soil near their entrance holes without obvious surface trails. Vole holes tend to appear in clusters near gardens, orchards, or anywhere with dense ground cover.
Silver-Dollar-Sized Holes: Chipmunks
Chipmunk burrow entrances are cleanly dug and about the diameter of a silver dollar, roughly 1.5 to 2 inches across. One telling feature is the absence of a dirt pile. Chipmunks scatter their excavated soil away from the entrance to keep the hole inconspicuous, so a clean, round hole with no mound in a yard or garden bed is a classic chipmunk sign. These animals are active during the day, so you’ll often catch the culprit in the act.
Larger Holes and Mounds: Gophers and Moles
Gophers and moles both push soil to the surface, but their mounds look different. Mole mounds are volcano-shaped with a roughly circular margin, while gopher mounds are crescent or fan-shaped with the entrance hole plugged from below. You typically won’t see an open hole with a gopher mound because they seal it after each trip to the surface. If you find a round, open hole 2 to 3 inches across with a kidney-shaped dirt pile, that’s more consistent with a ground squirrel or rat.
Moles also create raised ridges just below the surface as they tunnel through the top few inches of soil. If you see both volcano mounds and snaking ridges across your lawn, moles are the answer.
Holes Near Water: Crayfish Chimneys
In damp or poorly drained yards, especially near streams, ponds, or ditches, round holes surrounded by towers of mud pellets are the work of burrowing crayfish. These mud “chimneys” can stand 3 to 8 inches above the soil surface and have a large, round hole in the center. Up close, you may notice scrape marks in the fresh mud left by the crayfish’s claws. The tunnels extend down to the water table, which is why they only appear in consistently wet ground.
Snakes Use Holes but Don’t Make Them
If you suspect a snake is living in a ground hole, you’re probably right that a snake is there, but something else dug it. Snakes lack the limbs and claws to excavate soil. They adopt abandoned burrows made by rodents, chipmunks, or other digging animals. A round hole with no fresh dirt around it and no sign of the original occupant may now be home to a snake, particularly in rocky areas, along foundations, or near wood piles.
When It’s Not an Animal
Not every round hole has a living cause. In areas with limestone or other soluble bedrock, small depressions or holes that slowly widen could be the early stages of a sinkhole. Other non-animal explanations include ground settling over a decaying tree root, a collapsed section of old drainage pipe, buried organic material that has rotted away, or even a deteriorating septic system. These holes tend to grow over time rather than staying a consistent size, and they often appear near foundations, driveways, or old trees rather than in open lawn. If a hole keeps expanding or the surrounding ground feels soft and unstable, that warrants a closer look at what’s happening underground.