In some places the road had about 45cm between the outer wheel and the edge of the cliff.
There was little room for passing, and only where the bank came out in a few places could this be achieved.
It took great skill to drive the Wellington to Napier mail horse coach over the road - which generally travelled at walking pace only.
Entering the Woodville end of the Gorge Rd, known as the upper gorge, there was a bridge over the river, which was completed in May 1875.
Before this bridge was built, coach passengers were sent over the river in a cage on a wire rope, and would be put into a new coach on the other side.
The wire was apparently a terrifying experience and reported as "one of the most unpopular ever invented".
The bridge, which could take railway and road traffic, was designed by Mr Carruthers, engineer-in-chief of the railways.
The contractors, Messrs MacNeil and Dunn, employed 30 men on the job to complete the £12,000 (2017: $1.6 million) contract.
As the work was "dangerous and difficult", higher wages than normal were paid.
To pay for the bridge a toll was immediately introduced and George Ross won the contract to collect the tolls. The toll remained until 1907.
At the Ashhurst end of the gorge - or the lower gorge, a punt carried passengers, horses and coach across the Manawatu River.
A wooden bridge was opened there in 1887 (also tolled) to replace the punt, but a large flood in 1895 wrecked it due to its low profile (as predicted by some). Travellers were then forced to again use the punt.
The Manchester Road Board, which had collected the tolls on the bridge, said it had spent the money all over the district, and had no money for a replacement.
The government was also not interested in paying for it until Sir Joseph Ward came to power and agreed to fund half of the bridge (less profits made by the Manchester Road Board on the previous bridge).
It was decided that all local bodies in the surrounding area should pay a fair share towards the bridge as well as the government, and a commission was appointed to settle the proportions.
The bridge took some time to complete as the river was often in flood, and the piers had to be sunk deeper than first thought, meaning extra cylinders for this had to come from England, with the bridge being finally opened in June 1909.
• Correction: Last week's photo of the tram wasn't Napier as I was led to believe - it was in fact Invercargill in 1951.
• Michael Fowler (mfhistory@gmail.com) is a chartered accountant, speaker and writer of history