In actual fact, surnames often have a strange way of breaking cultural and geographic boundaries - just because someone was named MacDonald, does not mean that you are going to find their direct ancestors in the Scottish Hebrides. Equally, Scots named for a locality need not have actually lived there for centuries. The Scots have almost always been a 'mobile folk' and your ancestors would not necessarily have been tied to any one geographic location throughout their history.
The map opposite gives a rough idea of some of the areas of Scotland where specific clan names were prevalent, but should be used as a guide rather than as a research tool for the reasons outlined above. You can click on the map to link to a larger image which will make the smaller names easier to read.
Many Scottish surnames were derived from the places that people lived or from the occupations that the people in question carried out. Some are quite obvious - Taylor [tailor], or Faulkner [falconer/falconeer], while others are a little more obscure. The surname 'Pottinger' is said to have come from the old name for an apothecary, and a 'Baxter' was a baker. Many other names derive from Scots Gaelic and have been 'anglicised' - often appearing quite different from their original Gaelic form. Thus, MacTaggart comes from Mac an tSagairt, meaning "son of the priest" and MacIntyre comes from Mac an tSaoir, meaning "son of the carpenter".
Given names [or Christian names/first names] can be a great help to any genealogist seeking to trace their Scottish ancestors. Scots [particularly before the mid-nineteenth century] regularly followed a fairly well adhered to practice of naming their children for specific family members from the previous generation. This was, of course, not always done and cannot be used as the sole method of identifying family members, but it is a useful tool which can be used to aid your research.
Specifically, the naming pattern for children often went like this:
These were not always strictly adhered to, and the order can sometimes change [perhaps based on how close the family members were to the particular relatives in their daily lives].
A final point worth noting is that the spelling of surnames and first names was not as important in the past as it is today, and the appearance of a new spelling of a Scottish surname should not be met with any great surprise. Remember that, in a time before literacy was universal, people would not necessarily have known how to spell their names, and the clerks who recorded events about the lives of these people often simply wrote down what they heard - resulting in some very interesting surname spelling variations in the records!