Stanwell Park Rail Viaduct over Stanwell Creek, Railway viaduct in Stanwell Park, Australia.

The Stanwell Park Rail Viaduct over Stanwell Creek is a curved brick arch viaduct of eight 13.1-metre clear spans carried on brick piers, the tallest 34 metres above the creek bed. It stands 56.727 kilometres from Central station on the Illawarra line, high in the Stanwell Park amphitheatre. Span 6 is now a steel girder.

Construction began in 1918, when steel shortages during World War I forced engineers to use three million bricks. The work was completed in 1920 and is now a protected monument in New South Wales.

The viaduct was the crowning work of New South Wales' "brick arch era" of 1910-24, and its name comes from the creek it crosses high in the Stanwell Park amphitheatre. It is the only brick arch viaduct of its type and size in Australia, and the duplication works it served brought social and commercial benefits to the Illawarra region.

The viaduct carries the active Illawarra line 56.727 km from Central station, so it is seen from outside only, not walked. Trees and bushland now hide much of the structure from below; archival photographs show the arches and piers as they appeared before this growth.

In the 1990s, one arch was replaced with a modern steel girder to fix ground movement issues. This intervention shows how old structures are adapted to remain safe.