Allegheny Mound Ant

Facts, Identification & Control

Latin Name

Formica exsectoides


Allegheny mound ants have a reddish head and thorax. The abdomen and legs are dark brown to black. The workers vary in size from 3.2 to 6.3 mm. They do not sting, but they can bite if the mound is disturbed.

allegheny ant illustration

Behavior, Diet & Habits

The workers make galleries and tunnels in the ground. The tunnels extend as deep as almost 1 m (~3 ft) into the soil. As they dig, the workers pile the excavated soil up to make the mound. The mounds can reach records of about 5 m (~16ft)  in diameter, especially with older nests found in fields and wooded areas. The mounds that these ants build are frequently mistaken for fire ant mounds.

Allegheny mound ants nest in fields, pastures and wooded areas. They also live in playgrounds and residential lawns in rural and suburban areas. They do not usually enter homes, but workers often forage on patios and decks.

Allegheny mound ants eat insects and honeydew, a sweet substance produced by sap-feeding insects like aphids or scales. The workers protect aphids and other insects that produce honeydew. The ant workers sometimes damage trees and shrubs by chewing openings in the bark and spraying formic acid. This is done to kill trees that are shading the nests. If these ants are disturbed, they give off a distinct formic acid odor.

If Allegheny mound ants are nesting on a property, it is usually best to call a pest control professional. There are several methods they can use to control Allegheny mound ants.


Queens produce eggs that become workers and reproductives. To establish a new colony, a mated queen and a contingent of workers leave the colony to select a new nesting site.

Signs of Allegheny Mound Ant Infestation

The most visible sign of Allegheny mound ants is the mound, hence their name. Few other ants in the U.S. build as visible a mound. Other signs would be the workers as they forage for food.

More Information

The Allegheny mound ant is a type of mound-building ant in the United States. These ants are found along the Atlantic coast from Nova Scotia to Georgia. They are most common in the Midwest and Northeast.