The River-flat eucalypt forest or Coastal floodplain eucalypt forest is a critically endangered threatened ecological community that is primarily found in southeastern Australia, from southeastern Queensland, through New South Wales, to eastern Victoria, on alluvial soils of the coastal floodplains.

[1] The name chiefly refers to its riparian and floodplain landscape location and the predominant tree canopy being Eucalyptus, Angophora and/or Corymbia, which may exceed 40 m in height.

[4] Less than 30% of its original range remaining, the community is found within the following bioregions: South East Corner (SEC), Sydney Basin (SYB), NSW North Coast (NNC), and South East Queensland (SEQ).

The community is on Quaternary alluvial soils, which may be soaked, waterlogged or overflowed, which include the riparian zones close to rivers and creeks, floodplain and associated depressions.

Shrubs include Acacia floribunda, Prostanthera lasianthos, Breynia oblongifolia, Bursaria spinosa, Goodenia ovata, Pittosporum revolutum and Plectranthus parviflorus, in addition to scramblers, forbs and vines.