Much of our identity is wrapped up in our names. When it comes to determining the country of origin of your last name you have to be very careful. Some names seem so obvious that you may jump to a conclusion that is totally incorrect. Not all names are what they seem to be.
The first thing to look at is the ending of your name. Certain name ending are more likely to come from one country than another. When it comes to France, there are several ending that are seen quite often, they are ier and eau or oux. Names such as Grenier, Boudreau and Theroux fit this pattern. Now given the fact that France colonized all over the world, you may find names that would seem to be of French origin which really belong to native peoples and also Africans who were enslaved and took the names of their masters. Switzerland has a French speaking area where the language and the names are French but the people may or may not be ethnically French.
You can see by these examples that there is much more to determining the ethnicity of a name and its owner than just what it sounds like.
Another example is the name Esteves, which is Portuguese. There is also a name Esteve which is French and Estevez which is Spanish. They are all taken from the name Steven and at least in the Portuguese version mean son of Steven. In the Scandinavian countries names such as Svenson and Larson have the same meaning. But how do you tell if it is Norwegian, Swedish or Danish? You need to have more information than just the name.
When it comes to Irish names, if you are lucky enough to have the O in front of your name that is pretty obvious but there are other names that are shared with Scotland and England and even Normans which is the case with the Fitzgeralds.
Another problem with determining the country of origin of a last name is that the name may have been totally changed. In some cases it may have been shortened but in others it is a new name. This happened quite often as immigrants tried to fit in and also the local authorities in a town when they could not understand what a name was, they often spelled it phonetically and that often comes out quite different. Something like Bushy for Boucher or Gonye for Gagne. In another case, leRoi which means "the king" became King. In other cases the names were just Americanized, Drajewicz became Drake and Shalamuck became Palmer. These are actually people that I personally know so this is not just a rumor, these are true family stories.
While it may be interesting to try to determine the country of origin of a given name there is no guarantee that it won’t be taking you down the completely wrong road. It is more efficient to do a little research first to try to get a handle on the family story and then have fun trying to understand you name.