Barbara, have you started by looking on 1900 census for gr.father? This will tell you how many years he was in this country. Most Polish immigrants came via Hamburg or Bremen.Census will show other info. Also check naturalization records in state in which he may have applied. Nat. papers may show where he came from. If you have access to LDS family history library, they are best source, as they can help you find info also on ship passenger lists. Hope this helps. Good luck!