Shrubs, 20–40(–50) dm. Stems: twigs ± flexuous, new growth ˂reddish˃, glabrous, 1-year old reddish gray, older gray; thorns on twigs straight or slightly recurved, 2-years old deep chestnut brown to blackish, fine, 1.5–4 cm. Leaves: petiole length 25–30% blade, glabrous, densely sessile-glandular; blade elliptic-ovate to rhombic-ovate, (2–)3–5 cm, ˂widest towards base˃, thin, base broadly cuneate, lobes 3 per side, sinuses short to moderately deep, lobe apex acute to acuminate, margins serrulate, teeth with small glands, veins 5 per side, apex acute, abaxial surface glabrous, adaxial pilose young, soon glabrescent. Inflorescences 2–4-flowered; branches glabrous; bracteoles caducous, linear, margins glandular. Flowers 20 mm diam.; hypanthium glabrous; sepals narrowly triangular, ˂5 mm˃, margins glandular-serrate, ˂abaxially glabrous˃; stamens 10, anthers pink; styles 4. Pomes red, orbicular-pyriform, 8–12 mm diam., glabrous; sepals spreading; pyrenes 2–5.

Flowering Apr; fruiting Sep–Oct. Rocky hills, brush; 50–200 m; Ala., Ga., Tenn.

Crataegus alleghaniensis is known from a few locations in northeastern Alabama, Georgia, and Tennessee, and is apparently scarce.