The A99 road is entirely within the former county of Caithness in the Highland of Scotland. It runs generally north/northeast from the A9 at Latheron to Wick and to the A836 at John o' Groats. It was part of the A9 until the A9 classification was transferred to what had been the A895-A882 link between Latheron and Thurso. Between Latheron and Wick it follows, mostly, the route of one of Telford's roads.