Narrow-leaved Red Ironbark

Eucalyptus crebra is a tree that typically grows to a height of 35 m (115 ft) and forms a lignotuber. It has persistent thick, rough, deeply furrowed, greyish black "ironbark" from the base of its trunk to the small branches. Young plants and coppice regrowth have linear to lance-shaped or curved leaves 50–120 mm (2.0–4.7 in) long and 6–17 mm (0.24–0.67 in) wide. Adult leaves are linear to lance-shaped, the same dull green to greyish colour on both sides, 55–180 mm (2.2–7.1 in) long and 7–27 mm (0.28–1.06 in) wide on a petiole 7–20 mm (0.28–0.79 in) long. The flower buds are arranged in groups of seven, nine or eleven, usually on a branching inflorescence on the ends of branchlets. Each group is carried on a peduncle 2–13 mm (0.079–0.512 in) long, the individual buds on a pedicel 2–7 mm (0.079–0.276 in) long. Mature buds are club-shaped, spindle-shaped, or diamond-shaped to oval, 3–7 mm (0.12–0.28 in) long and 2–4 mm (0.079–0.157 in) wide and green to yellow with a conical to rounded operculum. Flowering has been recorded in most months and the flowers are white. The fruit is a woody cup-shaped, barrel-shaped or hemispherical capsule 2–7 mm (0.079–0.276 in) long and 2.5–6 mm (0.098–0.236 in) wide on a pedicel 1–6 mm (0.039–0.236 in) long.

The narrow-leaved ironbark grows in sandy soils in woodland and forest from Picton, southwest of Sydney, north through New South Wales and Queensland to the vicinity of Moreton Telegraph Station on Cape York Peninsula.

The tree has a hard, strong, and dark red timber, which has been used for sleepers and construction. A plank has been recorded as being used for Elizabeth Farm, Australia's oldest surviving European dwelling. It is used as a shade tree or to line roadways, and is also available as a cultivar. It is useful in honey production as the flowers are heavy in nectar and pollen; the resulting honey produced by bees is light-coloured and delicately flavoured.