Mockernut hickory is a large tree with a narrow to broadly rounded crown and stout, ascending branches.
Leaves are alternate, feather-compound, 8–15 inches long, with 5–9 (usually 7) leaflets; leaflets 3–7 inches long, 1–3 inches wide, broadest near the middle; margin toothed, upper surface yellowish green, shiny; lower surface paler, densely hairy with light orange or brown hairs. Crushed leaves smell spicy, like orange rind. Leaf stalk has dense hairs.
Bark is gray, grooves shallow; plates flat, tight, never shaggy.
Twigs are stout, brown to dark gray, very hairy at first, smooth later; pores pale; terminal buds distinctive: light tan, large (½ inch or greater), hairy.
Flowers April–May; male and female flowers separate on same tree; male catkins in threes, 4–5 inches long, hairy; female flowers 2–5, in hairy spikes.
Fruits September–October, with a dark reddish brown husk 1½–3½ inches long, widest at the middle; shell thick; nut strongly 4-angled, top long-pointed, kernel sweet, edible.