Workers are 1/16 to 1/8 inch long and monomorphic. Queens are as large as 1/4 inch long and species vary in color from light brown to very dark brown. The antennae have 12 segments and no club, the eyes are large, ocelli absent, and the pedicel has 1 segment (node). The gaster has a circle of hairs around the anal pore. Cornfield ants might be confused with species of carpenter ants except that the thorax is unevenly rounded. No stinger.

Cornfield ants can form large colonies with several thousand workers, but there is only Queen. mounds 10 inches in diameter might be visible in the landscape.

Cornfield ants will nest in rotted wood in perpetually damp places, but they may also nest in rotting stumps and mulch or under landscape stones at the perimeter of a structure. These are generally a nuisance pest that may indicate the presence of a moisture problem inside the structure.