A bald-faced hornet infestation is clearly identifiable by the presence of a nest.
You will find bald-faced hornet nests at least 3’ above the ground and as high as 60’ or more in trees and bushes, and occasionally on lights, fences, and under the eaves of buildings.
Nests have a mottled gray paper exterior that can be up to 2’ in length. Bald-faced hornets create this paper covering by collecting and chewing weathered and rotting wood. The wood fiber mixes with their saliva to become a paste similar to paper-mâché that the bald-faced hornet can then form into place.
There will also be many bald-faced hornets flying around and near the nest.