-mile (174.2 km) route, which needed few major engineering works, followed the River Don to Inverurie, via Huntly and Keith to a crossing of the River Spey, and then to Elgin and along the coast via Nairn to Inverness.
Branch lines to Banff, Portsoy, Garmouth and Burghead would total miles (49.1 km).
In 1923, it became part of the London and North Eastern Railway as its Northern Scottish area, passing on miles (536.7 km) of line and 122 steam locomotives, most of them 4-4-0 tender locomotives.
Although the railway had several branches, its remoteness has resulted in only its main line remaining today as part of the Aberdeen to Inverness Line.
The stations were The Inverness & Nairn Railway was authorised in 1854 to build a railway from Inverness to Nairn.
The Great North, still seeking to reach Inverness, had objected but withdrew after running rights over the railway were promised.
There were other junctions with the Highland Railway at Boat of Garten and Portessie, and at Aberdeen connections for journeys south over the Caledonian and North British Railways.
The railway opened short of rolling stock as only half of the twelve locomotives and twenty-four of forty passenger carriages ordered had arrived.
The carriage builders, Brown, Marshall & Co of Birmingham, stated that based on their experience they had expected the line to open at least two months late.
Its eventual area encompassed the three Scottish counties of Aberdeenshire, Banffshire and Moray, with short lengths of line in Inverness-shire and Kincardineshire.
Fish from the North Sea ports and whisky from the distilleries of Speyside became important goods traffic.