The most widely found category is that which contains surnames derived from a place easily recognizable when surnames were adopted.
When a man left his homeland and moved to another country, he was distinguished from his neighbors by the identity of his homeland -- Walsh hailed from Wales, Norman was from Normandy, Norris was Norwegian.
Some men were from cities well-enough known that the city was the distinguishing reference as in Paris. Towns were used in the same fashion, as were major rivers and geographic features. Less obvious now are those names which identified a man by the location of his house. John Atwood lived at the woods, but exactly which one has long since been lost. Other names can be traced to the exact locale where the first to bear the name kept his residence. As with the Patronymic designators, languages varied in the way a place was denoted, as in the Dutch name Van Gelder (from the county of Gelder). The Germans used Von as the French used de or De, and both often reflected aristocracy.
Surnames representing localities are easy to spot if they come from a specific geographical area or part of land: Marsh, Middleton, Sidney, or Ireland, for example. The evolution of language has made others are less obvious: Cullen ("back of the river"), and Dunlop ("muddy hill").
Some sources include: American Surnames by Elsdon C. Smith, Baltimore, 1969; A Dictionary of Surnames , by Patrick Hanks and Flavia Hodges, New York, 1994; Family Names: How Our Surnames Came To America , by J. N. Hook, New York, 1982.