Leaving the Hunter River in April 1827, Cunningham made the first recorded European discovery of the Darling Downs, along Glengallen Creek, on 5 June 1827.

Cunningham returned to Sydney where he reported to Governor Ralph Darling on the quality of the country, the timber and the potential for an access route to Moreton Bay.

[1] Cunningham reported to the New South Wales Government on the economic significance of the pass which connected the coast lands with the extensive pastoral country to the west, however, it was not until the late 1830s and early 1840s that pastoralists began to explore the potential of the Darling Downs.

Darling Downs pastoralists were faced with an expensive 800 kilometres (500 mi) trip to Maitland to carry wool to port and return with supplies to the stations.

[1] The discovery was announced in the Moreton Bay Courier, through which an appeal for construction of a road through Spicers Gap was launched.

Little public support was forthcoming and squatters Patrick Leslie and Fred Bracker put up most of the money to clear the road and lay a "corduroy" or pine log surface.

By early August, two drays had travelled to Ipswich using the new road, saving three days and approximately 100 kilometres (62 mi).

Alphen was rewarded for his discovery of the route through Spicers Gap by the New South Wales authorities and he built a public house.

[1] An early action of the Queensland Parliament was to appoint a Select Committee, consisting of Messrs Buckley (Chairman), Moffatt, Watts, Haly, Broughton, Raff, Taylor and Thorn, to inquire into the internal communications of the colony.

Also called to give evidence at the committee were FE Roberts, the Surveyor of Roads and Augustus Charles Gregory, the Surveyor-General.

On 25 August 1860, Surveyor Austin reported to Gregory upon the eligibility of Spicers Peak pass and the ineligibility of Cunningham's Gap.

Austin stated that "...the surveying and levelling of the line I have selected will occupy me about a month, so that at the close of the period or about the end of September, I shall be open for another duty".

In 1854, Nehemiah Bartley describing the Spicers Peak corduroy road wrote: " ...the place was naturally a bottomless morass, full of springs; the logs had rotted in the middle...It was an awful place for a horse, bullock or vehicle of any kind to face...A dense wall of scrub on each hand prevented escape...A man, on foot, could, by treading on the roots of the tree, get along, but a saddle horse or bullock team, could not do this.

"[1] Drainage was a vital aspect of Austin's design, consequently, drains up to one metre in depth occur on both sides of the road.

Inverted sections or shallow drains directed water across the road and slowed the flow to stop erosion.

The length of road contained with Main Range National Park measures approximately 4,500 metres (14,800 ft) long.

Some of the original pick and chisel marks occur on a section of basement rock on the road 65 metres (213 ft) west of Devil's Elbow.

[1] There are a number of other features associated with the road, including stone extraction quarries, side cuttings, a system of catch drains and culverts occurring along the entire length of the roadway.

[1] Spicers Gap Road Conservation Park was listed on the Queensland Heritage Register on 23 July 1999 having satisfied the following criteria.

[1] Spicers Gap Road is also significant as the site of the telegraph line that carried the interstate and telephonic traffic for 112 years from 1861 to 1973.

Designed with gently sweeping curves and low gradients to cater for the heavy transport of the day, Spicers Gap Road is a rare extant example of the application of engineering from the 1860s.

Engineering features, including a system of catch drains and culverts occurring along the entire length of the roadway, demonstrate technological achievement.

Located within the Main Range National Park, Spicers Gap Road is important for its aesthetic significance and in some areas it retains the ability to promote a sense of remoteness and ruggedness.

Designed with gently sweeping curves and low gradients to cater for the heavy transport of the day, Spicers Gap Road is a rare extant example of the application of engineering from the 1860s.

Engineering features, including a system of catch drains and culverts occurring along the entire length of the roadway, demonstrate technological achievement.