Historical survey plans were studied to document the distribution and ecological relationships of treeless native grasslands on the lowland Gippsland plain, eastern Victoria. Grasslands occupied about 600 square kilometres, mostly in the Sale—Maffra—Heyfield area, which receives about 600 mm mean annual rainfall. All grassland regions have been developed for irrigation farming and not a single remnant is known to survive. Topography and soils appear to be the major factors promoting grasslands. They occurred on flat plains on clay loam and loam topsoils, above a clay subsoil. Burning by Aboriginals probably affected plant composition but appears unlikely to have been the principal factor leading to treelessness.