[9] The section of the A18 Snaefell Mountain Road from Keppel Gate northwards to the Gooseneck corner near Ramsey was built on common grazing land that was transferred to the Crown following the sale of the Island's feudal rights by the Duke of Atholl after the Disafforesting Commission of 1860.

[10] As the A18 Snaefell Mountain Road is purpose-built, it reflects typical 19th century highway and railway construction practices, with many small-scale cuttings, embankments and revetments, and follows land contours with purpose-built graded sections intersected by right-angle bends, road junctions and sheep-gates.

[11] The A18 Snaefell Mountain Road has small metal milestones[12] from the period of James Garrow as Isle of Man Surveyor-General;[13] they are numbered numerically from Douglas to Ramsey.

In 2014, the National Geographic magazine nominated the A18 Snaefell Mountain Road as No 8 in the Top 10 Driver's Drives.

This 15-mile route between Douglas and Ramsey is the motorcycle-racing circuit used for the Isle of Man TT (Tourist Trophy) and the Manx Grand Prix.