Don't forget towns like Szarvas, which is in southern Hungary, but is still full of Slovak family names, because the place was completely depopulated under the Ottomans, and then resettled in the early-to-mid 1700s by mostly-Slovak immigrants. Unfortunately, nobody kept track of exactly where all the settlers came from; other than a few lists of escaped serfs who were the subject of lawsuits between landowners, there are basically no records of the prior lives of Szarvas's residents. My maternal-maternal-etc. line lived in Szarvas, so that's what I know about, but there are other towns like it scattered all over Hungary.
My maternal-paternal line is the other extreme: they lived in the Csallóköz (which is sort of a large island in the Danube between Vienna and Budapest), and they were about as purely Hungarian as it is possible to be -- but that entire area is now Slovakia.
I also have a large helping of Hungarianized German townspeople from places that are now in Slovakia (Losonc, Eperjes, Kisszeben, Gömörpanyit), a bunch of Slovaks from the valley between Besztercebánya and Zólyom, and my illegitimate great-grandmother's unknown father from somewhere in what is now south-central Slovakia.
(What they all have in common is that they were Lutherans. Well, except the Hungarians from Csallóköz; they were true thick-necked Calvinists.)
So definitely count me in: I have Slovak roots both geographically and ethnically. (But I will never be able to wrap my brain -- or tongue -- around the language. It uses consonants as vowels.)