The road from Glen Fruin to Loch Long was known as Scottish Gaelic: Rathad Mòr nan Gàidheal, (in English "The High Road of the Gaels/Highlanders").
It was originally built as a temporary private road on land leased from Luss Estates to facilitate construction of the Trident facility at RNAD Coulport thus avoiding heavy vehicles using narrow roads on the Rosneath Peninsula.
After lobbying by the local authority, it was agreed that it would be upgraded to adoptable standard and opened as a public road.
On the 2nd January 2024, oil was detected in the waterways by The Scottish Environment Protection Agency.
Following this detection, roadways in the area were limited, and a multi-council cleanup and repair operation began.