Perthshire
Perthshire straddled central Scotland, the northern two-thirds forming part of the highlands and the southern third part of the lowlands. This division gave the shire a strategic importance as a frontier zone. Its main town, Perth (also known as St Johnston) lay at the confluence of the valleys of the Rivers Tay and Earn, which formed the major routes into the highlands through the glens, towards the endemically violent and unstable areas of Invernessshire and Argyllshire to the north and west respectively.
