More than 50 species of carpenter ants live in North America, but only a handful regularly show up in homes and cause structural damage. The three you’re most likely to encounter are the black carpenter ant, the red carpenter ant, and the Florida carpenter ant. Each looks different, lives in a slightly different region, and has its own nesting preferences, but they all share the same habit of tunneling through wood to build their colonies.
Black Carpenter Ant
The black carpenter ant (Camponotus pennsylvanicus) is the most widespread and commonly reported species in the eastern United States and southern Canada. Workers are almost entirely black, though some have a slight reddish tint at the base of the legs. Their bodies are covered in short, silvery-white hairs that lie flat against the abdomen but don’t overlap much, giving them a sleek, dark appearance. Major workers can reach about half an inch long, making them easy to spot when they’re foraging at night.
This is the species most homeowners picture when they think “carpenter ant.” It nests in moist, decaying wood outdoors, particularly in dead trees, old stumps, and fallen logs, but readily moves into homes where water-damaged wood is available. Leaking window frames, porch supports, and bathroom walls are common entry points. Black carpenter ants are the primary structural pest species across the Northeast, Mid-Atlantic, and upper Midwest.
Red Carpenter Ant
The red carpenter ant (Camponotus chromaiodes) is closely related to the black carpenter ant and is often found in the same geographic range across the eastern U.S. What sets it apart is its two-toned coloring: the midsection, the narrow waist segment, and the legs are reddish to rust-colored, while the head and abdomen remain black or dark brown. The front edge of the abdomen also tends to carry a reddish tint. Another distinguishing detail is a dense layer of golden hairs on the abdomen that overlap the edges of each segment by at least half their length, something the black carpenter ant lacks.
Size varies considerably within a single colony. Minor workers measure roughly 6 to 7 mm, while major workers range from about 9 to nearly 14 mm. Queens are the largest caste, reaching around 15 to 16 mm. Nests are commonly found in and beneath rotting logs and stumps, with tunnels often extending down into the soil. Colonies also establish themselves in standing dead trees and in moist, degraded wood inside buildings. Because its coloring overlaps somewhat with the black carpenter ant, the golden abdominal hairs are the most reliable visual shortcut for telling them apart.
Florida Carpenter Ant
The Florida carpenter ant (Camponotus floridanus) is one of the largest ant species in the southeastern United States. It’s distinctly bicolored: the head and midsection are reddish-orange, and the abdomen is dark brown to black. Workers have long, coarse golden or brown hairs on their legs and antennae that are noticeably longer than their body hairs, giving them a shaggier look than their northern relatives.
This species ranges from North Carolina south through Florida and west into Mississippi. In Florida, workers are commonly called “bull ants” because of their powerful bite. When threatened, they bite and spray formic acid as a defense, a combination that makes encounters memorable. Florida carpenter ants are tree-dwelling by nature, nesting in dead branches, palm trunks, and rotting wood, but they move into homes readily, especially in coastal areas.
How Carpenter Ants Nest
All carpenter ant species share a critical trait: they don’t eat wood. Unlike termites, they chew through it solely to create smooth, clean tunnels called galleries where the colony lives. This means the wood they excavate has to go somewhere, and that debris is one of the clearest signs you have a problem.
A mature colony typically has a parent nest located outdoors in a stump, dead tree, or buried wood. Once the colony grows large enough, it establishes satellite nests, often inside nearby structures where wood stays damp. A satellite nest can be located up to 100 yards from the parent colony. Common indoor sites include wood around leaking chimney flashing, skylights, bathtub walls, doorframes, porch columns, soffits, and flat roof decking. Carpenter ants will also nest in fiberglass and foam insulation if it provides a suitable cavity. The key requirement for a satellite nest is moisture: if you have a carpenter ant problem indoors, you almost certainly have a moisture problem too.
Telling Carpenter Ants From Termites
Size is the fastest giveaway. Carpenter ant workers are large enough to see individual body segments with the naked eye, while most termite workers are smaller and pale, almost translucent. Carpenter ants also have a clearly pinched waist and elbowed antennae, while termites have thick, straight waists and bead-like antennae.
The debris they leave behind is equally different. Carpenter ant frass looks like rough, fiber-like wood shavings, similar to what comes out of a pencil sharpener. The bits are ragged and uneven, and a close look often reveals dead ant parts, soil, and cocoons mixed in. Fresh frass is loose and light, matching the color of the wood being excavated. Darker brown frass usually means the ants are tunneling through damp or rotting wood. Carpenter ants push this debris out through small holes in their gallery walls, so you’ll find it in neat piles directly below an exit point or fanned out slightly on a surface.
Termite frass, by contrast, consists of tiny, hard pellets about 1 mm long that feel gritty and hold their shape when you pinch them. Carpenter ant frass crumbles immediately. And if you see mud tubes running along a foundation wall, that’s a subterranean termite, not a carpenter ant. Carpenter ants never build mud structures.
Signs of an Infestation
The most obvious sign is seeing large ants indoors, particularly at night when carpenter ants are most active. A few ants in your kitchen during spring aren’t unusual, but a steady stream appearing in winter or consistently trailing along the same path suggests a satellite nest inside your walls. Winged carpenter ants (called swarmers) emerging indoors in late spring are an even stronger signal that a colony has been established inside the structure for at least two to three years.
Other signs include small piles of wood shavings near baseboards, window frames, or door casings; faint rustling or crinkling sounds coming from inside walls; and wood that sounds hollow when tapped. If the nest is behind a wall, the ants may disappear into a crack or hole, but the actual nest could be several feet away from that entry point.
Getting Rid of Carpenter Ants
The single most important step is finding the nest. Once you locate it, you can either physically remove it (a vacuum works for accessible nests) or treat it directly with an insecticide labeled for indoor ant control. Insecticidal dusts applied into wall voids where ants are nesting or foraging are one of the more effective indoor approaches, since the dust contacts ants as they move through their galleries.
When you can’t find the nest, baiting becomes the primary strategy. Liquid baits soaked into a cotton ball and placed on aluminum foil near active ant trails work indoors. Outdoors, granular baits placed in small piles near trails or around trees containing nests can reach the parent colony. The idea is that foraging ants carry the bait back and share it, eventually eliminating the colony at its source. For outdoor parent nests, liquid perimeter sprays provide additional control.
Regardless of species, reducing moisture is the most effective long-term prevention. Fix leaking flashing, replace water-damaged wood, improve ventilation in attics and crawl spaces, and keep firewood stored well away from the house. Carpenter ants can’t establish satellite nests without a moisture source, so drying out the wood they’d target removes the invitation entirely.