As stated by me on the Czech Republic board:
this is the A-H your ancestor came from:http://brainworker.ch/Oesterreich/Austria-hungary.png
where 12 different languages were spoken. Was there ever a mention of Slovakland, Slovakish, Czechoslovakia by a family member? If yes, your research is in present Slovak Republic. You did mention Prezov which is Presov, Slovak Republc.
After the fall of A-H several new countries were formed and one was Czechoslovakia which in 1993 separated into Czech Republic and Slovak Republic.
Being that you found a "Czech" on US census that to me suggest CZECHOSLOVAKIA. The word Czech was used most likely because Czechoslovakia is a bit long to write out into a tiny column on the form.
What "nationality" church your ancestor attended? http://www.differencebetween.net/miscellaneous/politics/diff...http://www.slovensko.com/slovakia/slo.htm
Your ancestors followed someone from the home village to Streator, Illinois. Might you know who?