The first crossing of the Murray River by white men occurred in November 1824 when Hamilton Hume and William Hovell led an expedition from Yass in search of an overland route to Westernport Bay.

Subsequently, many families took up parcels of grazing land on the rich river flatlands, among the first being William Wyse and Charles Ebden.

The drovers track that developed along the line of the advancing squatters, and subsequently by their excess stock returning for sale at Melbourne and Sydney markets, led naturally to the same point Hume and Hovell first sighted the river.

When the river was high after heavy rains or snow melting in the mountains crossing became difficult until a log punt was built in 1844.

[1] The concept of damming Australian rivers for irrigation and flood mitigation was first investigated back in the days of the steamers.

[4][1] Construction of the weir took seventeen years with the reservoir being completed and officially opened by the Right Honourable Lord Gowrie, Governor of NSW, on 21 November 1936 and a plaque on the northern pier of the dam commemorates the occasion.

[1] Three engineers of note were involved in formulating the agreement, Ernest de Burgh, the Chief Engineer of the Water Supply Branch of the NSW Public Works Department, J. S. Detheridge the Commissioner, State Rivers and Water Supply of Victoria, and G. Stewart in South Australia.

However, the Hume scheme appears to have been immune to any cuts due to the State - Federal agreement and advanced stage of the project.

[1] As a result of the construction of the weir, the water level in the Murray River backed up behind the dam to permanently inundate the floodplain, which was up to several kilometres wide in many places.

[5] The involvement of the NSW Public Works Department is also implied by photographs of components fabricated by Charles Ruwolt and Sons held by Museum Victoria.

It is therefore very likely that the New South Wales Public Works Department and Victorian State Rivers and Water supply commission were jointly responsible for the design and construction, as was the case with the Hume Dam itself.

These were assembled in situ with the use of a travelling crane running across the falsework and hot riveting of preformed, punched and cut angle and flat section steel.

At least one of the main trusses was trial assembled at Vickers Ruwolt's Burnley works, probably one of the largest structures to be erected in this fashion.

[1] The bridge was clearly seen as a landmark and complementary to the Hume Dam itself in terms of national pride and potential tourist value.

The State Rivers documented the bridge's construction and produced a series of lantern slides showing progress.

The Victorian Railways also produced its own series of photographs in the 1940s and 50s presenting the bridge as part of a dramatic landscape and engineering achievement, probably for promoting tourist visits(by train) to the region.

[2] The 13.7-metre (45 ft) approach span on the New South Wales side was constructed in 1963 as part of the upgrading of the Hume Dam.

In 2005 the waffle slab decking was replaced to raise their load capacity, new guard rails were installed and the NSW approach to the bridge was widened for safety reasons.

Because of its unique location, over the waters of a dam with the border running down the centre of the body of water, the Bethanga Bridge is the only built structure shared by both New South Wales and Victoria and listed on both the New South Wales State Heritage Register[1] and the Victorian Heritage Database.

In 2005 the waffle slab decking was replaced to raise the load capacity, new guard rails were installed and the NSW approach to the bridge was widened for safety reasons.

Elaboration in the form of variable depth from sloping upper chords as in the Camel-back arrangement, reduced the amount of steel required, and also dead weight for a similar strength.

The bridge was designed in New South Wales by Department of Main Roads engineer Percy Allen and the trusses were built by Vickers Ruwolt in Melbourne.

[1] Bethanga Bridge is of historical significance to tNew South Wales for its associations with the construction of Hume Dam.

[1] Bethanga Bridge is of scientific (technical) significance for the unusual use in Victoria of Pratt trusses, a predominantly NSW technology, its construction.

Bethanga Bridge is of historical significance to New South Wales for its associations with the construction of Hume Dam, a major national undertaking of the early twentieth century.

[1] The place is important in demonstrating aesthetic characteristics and/or a high degree of creative or technical achievement in New South Wales.

Bethanga Bridge is of technical significance for the unusual use in Victoria of Pratt trusses, a predominantly NSW technology based on American engineering practice .

It is also of aesthetic significance for the vast scale and length and the rhythmic patterning of repeated geometric motifs of the trusses.

[1] The place possesses uncommon, rare or endangered aspects of the cultural or natural history of New South Wales.