The earliest stone castles date from the 13th century. Examples include Urquhart Castle by Loch Ness and, on a smaller scale, Lochindorb north of Grantown-on-Spey.

The typical fortress from the 14th century onwards was essentially a tower, tall and square, with additions of further towers creating the Z- or L-plan castle. These exist today in various states of ruin or restoration throughout the Highlands. Though several are picturesquely abandoned - such as Ardvreck Castle by Loch Assynt in Sutherland or Castle Girnigoe by Wick, others are privately owned and occupied, such as Eilean Donan Castle.

From the 17th century onwards, more peaceable times resulted in the extension of many of these towers into more complex and comfortable dwellings, with domestic wings. Typical examples here include Dunrobin Castle in Sutherland, Cawdor Castle near Nairn, Dunvegan Castle on Skye and Castle of Mey in Caithness, favourite of Queen Elizabeth, the Queen mother. In addition, there are "modern" castles in the Highlands as well, often dating from the 19th century, which have never had a defensive purpose and are more accurately described as mansions.