Help me out with some ancestry/immigration (1900)?!?

-I am trying to find out about my ancestry! I found immigration cards of my family online and saw that they immigrated to the U.S. from the Russian Empire around 1905-1910. This is all very cool information, except for the fact that much of the Russian Empire in 1900 is not part of Russia today. Especially since my family was Jewish, I believe it is likely they were from Latvia, Lithuania, Poland, Ukraine, or Belarus (the Pale of Settlement). Apparently not many Russian Jews in 1900 actually lived in current day Russia territory. Is there any chance anyone can give me any leads from here? I would like to know the exact country they came from......This is all beginning to become very discouraging.





Don't know if this info helps, but they spoke yiddish. Also, on the immigration card there was a list of about 50 other families. For my family it specifically said they were from Russia, while for some other families it said they were from Lithuania and Poland (not countries in 1900)....hmmm??