The absolute best way to tell a nationality by last name is to research it with the aid of a genealogy expert, claims Ehow.com. There are a few sure-fire ways of telling certain nationalities' names, such as those from the Netherlands, which have fairly distinct characteristics.
For example, Dutch names can be identified quite easily if they possess certain features. Behind the Name provides a list of Dutch names, and many contain double-letter elements, such as "aa" in "Daalman" and "ll" in "Bulle." Many Dutch names also contain a double "j," which is rare in European languages. Thus, it is possible to distinguish between Dutch and English names based on these differences.