Passport applications are often a valuable source of genealogical information. NARA has passport applications from October 1795-March 1925. The U. S. Department of State has passport applications from April 1925 to the present.
Some immigrants applied for passports to return home to visit family or friends. These records usually give a place of birth or at least the destination (which is often the home town)
I have a Register of Passports 1834-1843 for all states at
The index to Passport Records and an explanation of Passport Records as a research tool is at
You can pass this message on to anyone you think might be interested, and if you find an ancestor on any of my projects please let me know!