Scotland is sub divided into 5 traditional regions in terms of whisky production (as recognised by the Scotch Whisky Association)
Lowland – whiskies such as Auchentoshan and Bladnoch tend to be light and floral.
Highland – whiskies such as Aberfeldy, Dalmore and Glenmorangie – A large region and a diverse flavour profile.
Speyside – whiskies such as Glenfiddich, The Glenlivet and Cardhu tend to be honeyed, fruity and light.
Islay – whiskies such as Lagavulin, Ardbeg and Bowmore tend to be smoky and phenolic (think TCP)
Campbeltown – whiskies such as Springbank and Glen Scotia tend to be peaty, briny and powerful.
Traditionally each region produced a distinctive style of whisky however with companies experimenting with new methods, casks and styles the lines that once divided the regions are now slightly more blurred.
There is an argument that there should be a sixth geographical region, The Islands, which would encompass all distilleries on the Scottish Islands with the exception of the Islay malts. Distilleries such as Arran, Jura and Highland Park are currently placed within the Highland region.
Most of the regional differences come about purely as a result of the varying topography and geography of Scotland. The best example of this is the heavily peated and phenolic style of whisky produced by the Islay distilleries. This character simply came about as the only fuel they had to burn in the distilleries maltings was peat, which gives it that unique flavour. Hence the differences between peated and unpeated whiskies, which until recently was mostly typical of Islay malts.
Nowadays even speyside distilleries are experimenting with peated barley. Tomatin and Glen Moray produce limited quantities every year of a lightly peated style.