The Lowlands region is the Southernmost part of Scotland.
But then again, most Lowland distilleries are located near
the Northern border of the region, roughly around the line
between Glasgow and Edinburgh (or the line from Dundee
to Greenock) - not far from the remains of Hadrian's Wall.

These borders are arbitrary anyway; The Inverleven is a
Lowland malt, while the Inchmurrin (distilled only a few miles
to the North) officially is a Midland (= southern Highland) malt.
The same goes for Glengoyne and Littlemill. The only Lowlanders
that are not distilled close to the Highlands border are Bladnoch and
Ladyburn. In fact, these last two distilleries are closer to Campbeltown
than to the other Lowland distilleries - both geographically and in the character of the malts that are produced there. I've never a been particulay fond of Lowland malts, but recently very good experiences with Bladnoch and older versions of St. Magdalene have tickled my fancy. I will investigate further...
(Kinclaith and Ladyburn have been closed.)

Meanwhile, here's a picture of some ruins of Hadrian's Wall that runs along the border between the Highlands and the Lowlands.

Now I know all this has very little to do with single malt whisky (the stuff wasn't even invented back then), but the story behind the building of the wall is so captivating that I couldn't help mentioning it. You can find a lot more information on this subject on the website of Aboutscotland.com.

The 73 mile long wall running from coast to coast was built almost two thousand years ago by the Roman emperor Hadrian - or rather by some people working for him. Looking at the remains of the wall it's hard to imagine how this wall managed to keep hordes of picts out of the Roman empire but the wall was actually a lot higher back then - and the people a lot shorter.