Pignut hickory is a medium-sized tree with a rather narrow crown, 2–4 times longer than broad.
Leaves are alternate, feather-compound, 8–12 inches long, with 5 (rarely 7) leaflets. Leaflets lance-shaped, narrow at base or near middle; margin toothed; tip tapered to a point. Upper surface yellow-green, smooth; under surface paler and smooth or hairy along veins. Bright yellow in fall.
Bark is gray, thin, tight, rough from numerous shallow, crisscrossing cracks forming close, flattened scales.
Twigs are rather slender, reddish-brown, smooth; pores pale.
Flowers April–May, male and female flowers separate on same tree; male catkins 3-branched, yellowish-green; female flowers few.
Fruits September–October, variable, usually pear- or egg-shaped, often with a necklike base; about 1¼ inches long; husk dark brown, thin, splitting late along 2–4 lines or not at all. Nut pear-shaped with a short beak.
Similar species: Distinguished from black hickory by 5 (not 7) leaflets, twigs that don't abruptly taper toward the terminal bud.