Long Cove Creek railway viaducts, Lewisham, Heritage railway viaducts in Lewisham, Australia.

The Long Cove Creek railway viaducts are three pairs of steel bridge structures that cross a small valley between suburban areas. Each pair spans approximately 27 meters and is supported by brick piers built into the creek bed.

The first railway here opened on 26 September 1855, and its largest structure was an eight-span stone arch viaduct west of Petersham. By the 1880s deterioration led to its replacement by three pairs of 27-metre Whipple trusses, replaced in turn by welded plate web girders in 1993. Two more tracks followed in 1892 with lattice trusses, replaced in 1998, and three pairs of riveted Warren trusses were added in 1925–27 for sextuplication.

The viaducts stand between Lewisham and Summer Hill, not in south-western Sydney. The name Long Cove Creek is still used for the waterway the Main Suburban line crosses here. A pair of 1886 Whipple trusses is kept on display beside the viaduct, and the 1926 Warren trusses still carry the main lines.

The viaducts are part of an active railway line and can be viewed from ground level or from the water's edge. Best access is from nearby footpaths that pass under or alongside the structures.

Original steel trusses from 1886 are preserved at the site, showing how American engineering methods were adapted for Australian railways. These remains help understand how railway technology moved between continents during that era.