The US government has issued passports to citizens traveling abroad since 1789. But except for short periods during the Civil War and World War I, passports weren’t required until 1941.
A non-naturalized immigrant couldn’t get a passport unless he’d formally declared his intention to become a citizen.
If your ancestor’s passport application is among the 1.5 million here, you’re genealogically set. A few I found include the applicant’s birthplace and year, occupation, hometown, length of uninterrupted residence in the United States, date and court of naturalization, reason for travel and appearance (for the man who submitted this application, right down to his “flat” nose).
According to NARA’s Web site, 95 percent of mid-19th century passport applicants were men. A man’s wife and children traveling with him were listed on his passport. Likewise, children traveling with only their mother were on her documents.
Later in the 1800s, women more often obtained passports in their own names. By 1923, they constituted more than 40 percent of applicants.
The records are available with a $155.40-per-year subscription to Ancestry.com, or you can order copies from NARA. Note passports issued March 4 and 5, 1919, are missing from NARA’s film and from Ancestry.com’s database.