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Carpenter ant — identification photo
Carpenter ant · Camponotus pennsylvanicus
AntsNH resident

Carpenter Ant — Quick ID for New Hampshire Homeowners

Also called Black carpenter ant

Carpenter ants are New Hampshire's largest house ants — up to 13 mm, black, with a single smoothly rounded thoracic hump. They don't eat wood; they excavate smooth galleries and push out frass (sawdust-like shavings). UNH Extension names them NH's most troublesome structural ant pest. Nail the size-and-frass ID here; treatment and the termite comparison live in the full ant guide.

At a glance
Size
6–13 mm
NH's largest ant; Camponotus pennsylvanicus
Damage tell
Frass piles
wood shavings + insect parts at kick-out holes
Galleries
Smooth, sanded-looking
no mud inside (the termite separator)
NH status
Very common
top structural ant pest in NH per UNH Extension
The short of it

Is it a carpenter ant?

Carpenter ants are the largest ant you are likely to find in a New Hampshire home — big, black, and impossible to miss when they trail across a kitchen counter at night. UNH Cooperative Extension identifies them as the state's most troublesome structural ant pest, and finding frass or winged swarmers indoors means the colony has moved in.

Treat this page as the size-and-frass check. When you need treatment strategy, the termite comparison, and what indoor frass really signals, the complete Ant FAQ guide above has it.

Identify it

Quick carpenter ant ID

Size and frass separate carpenter ants from every other ant in New Hampshire.

Species profile

Carpenter ant

Scientific name
Camponotus pennsylvanicus (also C. novaeboracensis)
Family
Formicidae
Size
6–13 mm (workers vary; queens larger)
Coloration
Dull black; some individuals have reddish-orange midsection
Habitat
Moist or decayed wood — window and door sills, roof sheathing, decks, framing near tubs and dishwashers; satellite nests indoors
Active season
Year-round indoors; peak foraging spring through fall; winged swarmers in spring
Diet
Insects, other invertebrates, honeydew from aphids, household food scraps
Reproduction
Winged males and queens swarm in spring; queens establish new colonies in soft wood
Lifespan
Workers live months; queens can live a decade or more

Very common throughout New Hampshire; primary structural ant pest in the state according to UNH Cooperative Extension.

The tells — key ID features

  • Large and black with one smoothly rounded hump on the thorax (single-node waist) — the profile separates it from pavement and odorous house ants.
  • Frass piles: clean wood shavings mixed with insect parts and sand below kick-out holes — carpenter ants push this out of their galleries.
  • Smooth, sanded-looking gallery walls with no mud inside — the termite separator (termite galleries contain soil and mud tubes).
  • Winged swarmers (alates) emerging indoors in spring strongly indicate an established nest inside the structure.
Is it actually this? — the confusion species

Eastern subterranean termite

How to tell — Termites have straight antennae, no waist, and pack galleries with soil; carpenter ants have elbowed antennae, a distinct waist, and leave clean frass with no mud.

Odorous house ant

How to tell — Odorous house ants are much smaller (2.4–3.3 mm) and smell like rotten coconut when crushed; carpenter ants are 6–13 mm with no distinctive odor when crushed.

What you'll notice

Signs of a problem

Two signs pinpoint an established infestation.

Small piles of sawdust-like frass (wood shavings + insect fragments) below a sill, baseboard, or door frame

What it means — Active carpenter ant gallery above — workers are excavating and pushing out material.

Large black ants trailing at night or winged swarmers at a window in spring

What it means — Established colony; swarmers indoors in spring confirm the nest is inside the structure.

When it's past DIY

Carpenter ant control in New Hampshire

Carpenter ants are NH's most troublesome structural ant pest. Finding frass indoors or winged swarmers at a window in spring means there is an active satellite or parent nest inside the structure. Professional treatment locates the colony and eliminates it. The full ant guide covers treatment options, moisture correction, and the termite comparison.

Signals it's past DIY

When to call a pro

  • Frass piles appear under a sill, frame, or baseboard.
  • Winged swarmers emerge at a window or light fixture indoors in spring.
  • Large black ants are seen regularly trailing at night.
  • You need carpenter ant vs. termite confirmation before damage spreads further.

Not sure it's a carpenter ant?

A licensed NH technician can confirm the species and tell you honestly whether it's a DIY fix or a job for a pro — free inspection, same-day service across Southern New Hampshire.

Get a Free Inspection(603) 785-0118
Common Questions

Frequently asked questions

Sources(2)
  1. [1]
    UNH Cooperative Extension — Carpenter Ants

    most troublesome structural ant pest in NH, frass ID, gallery description

    extensionverified 2026-06-30
  2. [2]
    Anchor Pest — Ant FAQ Guide

    full NH carpenter ant treatment and termite comparison

    industryverified 2026-06-30

Written & reviewed by

Verified

Daniel Brady

NH-Licensed Pesticide Applicator · License #782664 (NHDAMF, RSA 430)

Daniel Brady is the New Hampshire–licensed applicator behind Anchor Pest Services, a family-owned pest control company serving the Manchester area since 2017.

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Last updated 2026-06-30

New Hampshire pest control

Dealing with carpenter ants in your home?

Anchor Pest Services identifies and handles carpenter ant problems across southern and central New Hampshire. Family-owned since 2017, NH license #782664.

Get a Free Inspection(603) 785-0118
  • NH-licensed applicators (#782664)
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