Oh, far as where my family hails from, my grandparents on my father's side are Czech (bohemian, I believe). I think they immigrated to the US as children. Though we actually had an extensive family tree professionally done/made, I'm fuzzy on the exact details and don't have a copy of it myself. My father and his brothers were born in the US, though, and did not learn the language (something I find very, very regretful, because I know I'd have loved to have been raised bilingual.
From my mother's side it's British, Scottish, and some Irish. An extensive family tree has not been made to my knowledge, so I can't give any specifics . The relatives I know (it's a HUGE family) on that side were all born in US.