The Strathisla distillery in the town of Keith is generally believed to be the oldest continuously existing distillery in Scotland. It was formerly a monastic brewery, but began distilling whisky in 1786. There is a strong argument to say that it is the most beautiful distillery in the Highlands.
The distillery has not always been known as Strathisla (although the whisky itself has generally been called Strathisla). It was known as Milltown until 1870 when it became Strathisla distillery. In 1890 it became Milton distillery (not to be confused with Miltonduff!) until finally reverting back to Strathisla in 1951. Bottlings can still be found of Strathisla that were distilled before World War II.
Strathisla is the "spiritual home" of Chivas Regal; this helps to explain why there are relatively few official bottlings and that most Strathisla whisky is bottled by Gordon & MacPhail.