Tracing Immigrants Country of Arrival Records
See Coming to America: Finding Your Immigrant Ancestorsin the FamilySearch Learning Center.
The best sources for determining an immigrant ancestor's place of origin are usually those made in the country of arrival, not the country of origin. Most immigrants spent much of their adult lives in their new countries, so more records exist for them there. It is usually easier to search country-of-arrival records because it is easier to find out which jurisdictions kept records about the immigrant. You will have more success if you use all available country-of-arrival records.