No, I take it back: I was seduced by folk etymology, as Eugene Volokh is too polite to suggest. Any scrap of authority in what I said about Finland = 'fen land' is wrong. See this posting, among others:

The Finn/s name originally referred to the Sami (see for instance Tacitus "fenni". In Norway this seems to have been the case also in modern times. The Finns call themselves "suomalaiset".

Finn/s is probably formed from Finland and not the other way round. It is probably a terrain name: German Finne, Celtic penn (summit). Might also have something to do with the verb "finna" in Swedish and mean "searcher, finder". If the Celtic finn means white it has nothing to do with the name of the people in Finland.

This dates the name "fenni" back to Tacitus (Roman, ca. AD 55-117). It's still conceivable that English "fen" has a root related to the German "Finne" cited above, but that's not attested anywhere, so it's just a theory: Some suggest a connection with fen. Most serious discussions have "Finn" from Swedish "finne", connected to the root of English "find".