It has been branded "deadly" and "frustrating" and last week was closed by floods, landslides and a bomb scare.
Flooding made the A9 a nightmare last week
But now the A9's notoriety has a supernatural edge after the Highland stretch appears on a list of Britain's top 10 spookiest roads.
The main trunk route is mentioned twice at numbers two and eight.
Building materials supplier Tarmac produced the list. The M6 comes first after reported sightings of Roman soldiers and a ghostly woman.
Tarmac put the A9 in the Highlands as the second most haunted after a family reported seeing an ornate coach and horses, along with bewigged footmen.
The road appears again at number eight following a sighting of a Victorian-clad man on a horse at The Mound between Dornoch and Golspie.
Last week, the A9 in the Highlands was severely affected by flooding which also uncovered four unexploded bombs on a riverside leading to the road being closed temporarily at Alness.
1 The M6
2 The A9 in the Highlands
3 Platt Lane, Leigh, Manchester
4 High Street and Suffield Road in Great Yarmouth
5 Gloucester Drive, Finsbury Park, north London
6 The B4293 at Devauden, Wales
7 The B3314 near Tintagel, Cornwall
8 The Mound, on the A9 near Dornoch
9 The B1403 near Doncaster, South Yorkshire
10 Drews Lane, Ward End, Birmingham
A study commissioned by Highlands and Islands Enterprise found businesses labelled the route frustrating, while over the years politicians have called for it to be upgraded to a dual carriageway.
The M6 tops Tarmac's list - timed for Halloween - with its reports of phantom Roman soldiers, a ghostly woman and lorry driving against the flow of traffic.
Other incidents reported included eyes looking out from bushes in Platt Lane, Leigh, Manchester - the scene of a mining disaster years previously.
There were reports of a phantom dog on Great Yarmouth High Street and ghostly children playing in Gloucester Road, Finsbury Park, north London.
A guardian angel voice allegedly alerted a woman driver of an out-of-control car on the B4293 in Devauden in Wales and a lady in Victorian dress was reportedly spotted on the B3314 near Tintagel in Cornwall.
Tony Simmons, sightings co-ordinator for Tarmac, said: "We compiled the top 10 on the basis of the clarity of sightings rather than just the number of spooky experiences.
"At this time of year it's easy to mistake swirling mist for something more sinister and we wanted to make sure we were listing truly spooky sightings."