|Length:||10.5 miles (16.9 km)|
|Meets:||A857, B8027, Unclassified|
|Route outline (key)|
The A866 is approximately 10.5 miles long and links Stornoway to the Point District of Lewis. Road signs are bilingual, in English and Gaelic.
Stornoway - Portnaguran
The road commences in Stornoway (Steòrnabhagh) at the ferry terminal where Caledonian MacBrayne ferries sail to Ullapool. It heads east as South Beach, becoming James Street, and then Sandwick Road, passing through the Plasterfield (Achadh a Phlastair) district, and then Sandwick (Sanndabhaig) as East Street. It passes an unclassified road to Melbost (Mealabost) and Stornoway Airport, and becomes the Braigh Road as it crosses the narrow isthmus to the Eye Peninsula or Point district of Lewis (An Rubha).
Entering the Eye Peninsula it passes an unclassified road to Eagleton and Aignish (Aiginis), runs through the village of Knock (An Cnoc) and passes unclassified roadd to Swordale (Suardail) and Lower Bayble (Pabail Iarach) before entering the village of Garrabost. Continuing north east it passes an unclassified road to Upper Bayble (Pabail Uarach), the village of Shulishader (Sulaisisdar), an unclassified road to Seisiadar, and an unclassified road to Flesherin (Fleisirin). It enters the village of Aird as Barraid Mhicsuain, and continues on to the village of Broker (Brocair) where it turns sharply left on meeting an unclassified road to Portvoller (Port Mholair) and Tiumpan Head (Rubha an t-Siumpain). The road ends at the edge of Portnaguran (Port nan Guiran), presumably at the point where the road narrows - although older maps suggest the road once reached the coast in the centre of the village.