The largest hornet you’ll find in Pennsylvania is the European hornet, with workers reaching about an inch long and queens stretching to 1.3 inches. It’s the only true hornet established in the state. But several other large wasps, including cicada killers and bald-faced hornets, are commonly spotted and often mistaken for something more exotic. Here’s how to tell them apart and what to do if they’re nesting near your home.
European Hornets: Pennsylvania’s Only True Hornet
European hornets are the real deal when it comes to large hornets in Pennsylvania. Workers measure about an inch, and queens can hit 1.3 inches. Their coloring is distinctive once you know what to look for: a red and yellow head, a reddish-brown thorax, and an abdomen that’s brown near the front and mostly yellow toward the back, marked with brown teardrop-shaped spots.
These hornets nest inside cavities like hollow trees, wall voids, and attic spaces rather than building exposed nests in the open. One behavior that catches people off guard is that European hornets fly at night. They’re attracted to porch lights and illuminated windows, which is unusual for wasps and hornets. If a large, loud, brown-and-yellow insect is buzzing around your outdoor lights after dark, it’s almost certainly a European hornet.
European hornets are also the species most commonly mistaken for the northern giant hornet (formerly called the “murder hornet”) in eastern North America. That insect has never been found in Pennsylvania. It has only been detected in Washington State and adjacent British Columbia. If you think you’ve spotted one in PA, you’re looking at a European hornet.
Cicada Killers: Big but Mostly Harmless
Eastern cicada killers are the largest wasps most Pennsylvanians will ever encounter. Females can reach a full 2 inches in length, and males grow to about 1.5 inches. They have dark orange heads and thoraxes that darken to black on the abdomen, with three light yellow stripes and an orange tinge to their wings and legs. Their overall look is darker than a European hornet, with more black on the abdomen.
Despite their intimidating size, cicada killers are solitary wasps. Each female digs her own burrow in dry, sandy, or well-drained soil, creating tunnels that can run 12 to 15 inches deep and up to 36 inches long. You’ll notice a horseshoe-shaped dirt mound at the entrance. If you see many of them in one area, it’s because they all independently found the same patch of good soil, not because they’re forming a colony.
The practical upshot: cicada killers are very unlikely to sting you. They don’t defend a communal nest with a queen and brood the way social wasps do, so they lack that aggressive defensive instinct. Males will sometimes “dive bomb” your face if you walk through their territory, but males physically cannot sting. Females have a stinger they use to paralyze cicadas for their larvae, but they’re mild-mannered toward people. You can generally coexist with them safely.
Bald-Faced Hornets: Black, White, and Aggressive
Bald-faced hornets are technically a type of yellowjacket, not a true hornet, but they’re large enough to make the list. Queens, the biggest members of a colony, reach about 20 mm (just under an inch). They’re easy to identify: black bodies with ivory-white markings on the face, thorax, legs, and abdomen. No yellow or brown at all.
Their nests are the most recognizable of any wasp in Pennsylvania. They build football-shaped, grey papery structures that hang from trees, shrubs, or building eaves. Nests sit at least 3 feet off the ground and sometimes as high as 60 feet up in a tree. In Pennsylvania, these nests can grow to 24 inches tall and 18 inches across by late summer.
Bald-faced hornets are considerably more defensive than cicada killers or even European hornets. They will aggressively protect their nest if they perceive a threat. Give any active nest a wide berth.
How to Tell Them Apart Quickly
- European hornet: 1 to 1.3 inches. Brown, red, and yellow coloring. Nests in cavities (tree hollows, walls). Active at night around lights.
- Eastern cicada killer: 1.5 to 2 inches. Dark orange to black body with yellow stripes. Burrows in the ground. Solitary and docile.
- Bald-faced hornet: Up to about 0.8 inches. Black and white only. Builds large grey paper nests in trees or on structures. Highly defensive.
- Yellowjackets: Up to about half an inch (queens of some species slightly larger). Yellow and black banded. Often nest underground or in wall voids. Aggressive, especially in late summer.
What About Northern Giant Hornets?
Northern giant hornets (the species widely called “murder hornets”) are not in Pennsylvania. They have only ever been found in Washington State and nearby British Columbia. Queens of that species exceed 2 inches with a 3-inch wingspan, which is noticeably larger than anything established in the eastern U.S. They have yellow heads, black thoraxes, and yellow-and-black striped abdomens.
Penn State Extension specifically notes that European hornets are the species most frequently confused with northern giant hornets in this part of the country. The key differences: European hornets have reddish-brown coloring on the thorax and brown teardrop markings on the abdomen, while northern giant hornets have a mostly black thorax with a yellow spot between the wings and more uniform banding. If you’re in Pennsylvania, you can safely rule out the northern giant hornet.
Dealing With a Nest Near Your Home
Timing matters more than anything else. Colonies of European hornets and bald-faced hornets naturally die off over winter. Only new queens survive to start fresh colonies in spring. If you discover a nest in September or October and it’s not in a high-traffic area, you may not need to do anything at all.
If a nest does need to go, early in the season (May or June) is the safest window. Colonies are small, and fewer insects means less risk. All nest work should happen at night, when the insects are inside the nest, less active, and have difficulty seeing. Stay 10 to 15 feet away initially to observe flight paths before approaching.
For small exposed nests, a ready-to-use aerosol spray applied directly into the nest opening is effective. For nests inside wall cavities or underground, dust-based products work better because they penetrate deep into the space. Foams are another option for cavity nests. Spraying only the outside of a nest without treating the entrance is counterproductive: it angers the colony without eliminating it, increasing sting risk for days afterward.
Protective clothing is important regardless of the species. Thick, loose-fitting clothes (or a bee suit) with pant legs tucked into boots or taped at the cuffs, plus eye protection, will reduce your exposure. Professional pest control, which typically costs over $100, is worth considering for large nests, nests in hard-to-reach locations, or anyone with a known allergy to stings. Professionals carry liability insurance that covers property damage during treatment, which matters when nests are inside walls or attic spaces.
For cicada killer burrows in your lawn, the best long-term fix is changing the conditions they prefer. They choose bare, dry, sandy patches in full sun. Thickening the turf with grass seed and adding mulch or ground cover makes the area less attractive for future nesting seasons.