Built between 1856 and 1859 to encourage settlement of the isolated Ohariu Valley, the misnamed Old Coach Road is a rare example of an intact, original nineteenth-century public works thoroughfare. When the New Zealand Company sold the valley sections in 1841 the track used by local Maori was converted into a short, rudimentary road to cater for the new settlers. Despite this, few new owners chose to occupy their land and in 1854 only three pakeha settlers were living in the area. In 1858 the first superintendent of the Wellington Province, Dr. Isaac Featherston [1813-1876], suggested the reason the district had remained 'a waste and unoccupied for seventeen years' was the lack of adequate access to the valley. Granted the power to provide roads under the 1854 Roads Act, the Wellington Provincial Council advertised in the Wellington Gazette in 1856 for labourers to build a road between Ohariu Valley and the nearby Johnsonville settlement. Work began on what is now known as 'Old Coach Road' in late 1856. Labourers working on the road complained about the bleak conditions and poor pay and in 1857 the road was still unfinished. The Council set aside £1500 for the road and passed the Ohariu and Makara Roads Act, enabling them to levy rates on owners of land served by the road. The settlers did not support this move and many refused to pay the rates. In 1858 the council decided to extend the road, which had reached Ohariu Valley earlier that year, to increase the benefits for more rated owners. The tender was won by Lewis Brown and Frederick Darby and the road, then known as 'Ohariu Road', was finally completed in 1859. The improved access to the valley encouraged settlement and the population of the area increased. As the road had been designed primarily for the bullock teams used to haul logs from the valley to the mill at Johnsonville, the gradient was too steep for use by horse teams or coaches . In 1863 the lack of coach access prompted the Council to provide another road to the valley. Built between 1864 and 1866, 'Ohariu Road No.2' was constructed on a more gradual gradient and on a lower elevation than the earlier road. As a consequence, the new road soon became the main access route to the valley. Old Coach Road became known as Ohariu Road No.1. It continued to be used by local farmers but lower usage of the road prompted the Johnsonville Town Board to propose its closure in 1897. No action was taken and it continued to be maintained as a legal road. Paradoxically, during the mid-twentieth century the road was identified by the misnomer 'Coach Road' or 'Old Coach Road'. Due to its use for access to new housing divisions on the Johnsonville end of the road in 1945 and 1971, some sections of the road have been sealed. Other areas of the road were modified in preparation for use of the road for public works developments in 1963. In 1992 developers widened short sections of the road and 250 metres of it were covered with fill. The scale of the changes proposed by developers encouraged the Johnsonville Residents Association to seek official recognition and protection for the historic road. Protection for the full length of the road was gained in 2001 and Old Coach Road, now used primarily for recreational pursuits, remains one of New Zealand's best examples of an original nineteenth-century public works thoroughfare.

The hillsides between the two settlements were cleared of bush and then cut away to create a flat ridge that formed the basis of the road. This 'bench cut' construction technique involved the removal of large amounts of clay and rock. On some slopes this fill may have been used to build up the outside edge of the road but, as a hard outside edge was considered preferable, the full width bench of 4.2 metres was generally cut into the base rock. Some of the greywacke removed from the hillside may have been used to metal the road. Close to the bottom of the hill, near the Ohariu Valley, two culverts were constructed where the three-kilometre road passed over watercourses. In accordance with the normal building practices of the period, the road was built on the easy and constant gradient of between 1 in 12 and 1 in 15 that was required by non-motorised transport. The winding character of the road is a reflection of the need to maintain this constant grade. Part of the original road has since been sealed due to the development of new housing divisions on the Johnsonville end of the road in 1945 and 1971 (please note that sealed portions of the original road are not included in this registration). Other areas of the road have been modified in preparation for use of the road for public works developments in 1963 and in 1992 developers widened short sections of the road and 250 metres of it were covered with fill.