The foundation stone went down on 11 December 1823, and for roughly two years convict gangs hauled the bridge into existence by hand. The sandstone came from Butchers Hill, just upstream, and the men moved it the way men moved everything in a penal colony: on their own backs, in hand carts, block by block. They called it Bigge's Bridge at first, after John Thomas Bigge, the Royal Commissioner who had flagged the need for a crossing here in 1820. The name did not stick, but the bridge did. Six graceful arches spring from angled sandstone fins, set to part the flow of the Coal River. For a decade after its completion in 1825, it held the longest bridge span in Australia. Two centuries on, it remains one of the most photographed structures in Tasmania, a working monument to coerced labour that has long outlived everyone who suffered to raise it.

The plaque on the bridge names William Hartley Wilson as Superintendent of Stonemasons, and for a long time that was the whole of his recorded glory. Then his descendants went digging. Records held in Sydney's Mitchell Library confirmed something the family had long suspected: Wilson had also served as Colonial Architect of Van Diemen's Land, the very first to hold the role while the island was still governed from New South Wales. He was no trained architect. Lieutenant Governor Sorell had simply appointed him because no one better was available, the practical improvisation of a colony making itself up as it went. Wilson did the job until David Lambe arrived to take over as the first architect of Tasmania once it became a colony in its own right in 1825. The bridge is, in a sense, the work of an amateur who got it exactly right.

The Richmond Bridge you see today is not quite the one Wilson finished. In its first decades it was a leaner, plainer thing. The bulky hexagonal cutwaters jutting from its middle piers were added in 1884 and 1885; before that, the central piers wore the same simple vertical cutwaters still visible at the water's edge. The town-side approach was regraded in the 1830s for safety, smoothing a slope that once mirrored the gentler eastern end. Researchers reconstructing the bridge's original 1825 appearance commissioned the Hobart artist Joan Humble to paint it as it first stood, surrounded not by the European grasses and willows that crowd the banks now, but by the native reeds and shrubs of the Coal River valley. Many who study Tasmania's old stonework think the bridge was finer in its first plain form, its lines more balanced before the colony decided to dress it up.

Most bridges of its age are relics, fenced off and admired from a distance. Richmond Bridge simply kept working. Cars roll across it daily on the road north from Hobart, an unbroken line of use running back to the reign of George IV. In 2005 it was added to the Australian National Heritage List as an outstanding historic place, and Engineers Australia marked it with a Historic Engineering Marker, a nod from modern builders to the convict crews whose names mostly went unrecorded. Stand beneath an arch and the engineering reads clearly: dry-laid sandstone, shaped by hand, carrying loads its makers could never have imagined. It is rare for a structure to be both a museum piece and a piece of working infrastructure. This one has been both, without interruption, for two hundred years.