What this directory covers
This page lists every naturalized US citizen who has served in the US Congress, from the 1st Congress in 1791 through the current session. In total we track 125 members across 38 birth countries — representing 64 seats in the House of Representatives and 61 in the Senate. Each entry identifies the member's birth country, chamber, state, party, and years of service, and links to a dedicated profile page with a term-by-term election history.
The point of aggregating them on one page is to see the scale. Naturalized-citizen representation has never been a majority of Congress in any session, but it has been a constant feature of American legislative life for more than two centuries. Early entries were overwhelmingly from the British Isles. Nineteenth-century members arrived from Germany, Switzerland, and central Europe. The second half of the twentieth century widened the pool to include members born in Cuba, Vietnam, Mexico, India, Somalia, Taiwan, Nigeria, and many others. The twenty-first century directory is the most geographically diverse in Congressional history.
Alongside the biographical data, each member profile carries a cross-reference most voter rolls do not: does the member's country of birth extend the same political rights to its own non-native-born residents that the United States extended to that member? The answer, in most cases, is no. The directory makes that asymmetry visible member by member.