Eucalyptus longifolia grows as a tall tree with a large trunk diameter. The long narrow leaves are lanceolate (spear-shaped) and measure 10–25 cm (4–10 in) long and 1.5–2.6 cm (0.6–1 in) wide. They are a uniform grey-green or blue-green in colour. The white flowerheads are arranged in groups of three, and droop.m (AVH)
The range is from central New South Wales south to the Victorian border. In the north of its range it is more scattered in its distribution, but becomes more common south of Nowra to Bega. It generally grows on clay soils and floodplains, sometimes in areas with poor drainage, in valleys and low areas.
The dark red timber is hard and resistant to water, and termites. It has been used in and other general construction. The woollybutt is also important in beekeeping and the honey industry. It is useful as a shade tree or windbreak in paddocks, but grows too large for the average garden.