What the Congress Birthplace Tracker does
The Congress Birthplace Tracker is an independent, non-partisan database that identifies every naturalized citizen who has served in the US House of Representatives or US Senate, and cross-references each member's birth country against that country's own laws on non-citizen voting and legislative service. It currently covers 125 members across 38 birth countries, spanning the 1st Congress in 1791 through the 2026 session.
The US Constitution requires only that members of Congress be US citizens — seven years of citizenship for the House, nine for the Senate. It places no restriction on where they were born. That openness has produced a steady stream of foreign-born lawmakers: Albert Gallatin, the Geneva-born Secretary of the Treasury who first served in Congress in the 1790s; Matthew Lyon, the Irish-born Representative jailed under the Sedition Acts; and in the modern era, members born in India, Vietnam, Cuba, Somalia, Mexico, and Taiwan. The full directory is on the members page; an index of birth countries is on the countries page.
The second half of the tracker is about reciprocity. For every birth country in the database, we record whether non-native-born residents are allowed to vote or serve in that country's own legislature. 14 of the tracked countries currently ban non-citizen voting entirely. 16 allow it in limited forms — usually only in local or municipal elections. Only 5 grant broad voting rights to non-native-born residents. The result is a sharp contrast: the United States has repeatedly sent naturalized citizens from countries that would not, in the reverse scenario, let a naturalized American cast a single ballot.
Browse the full member directory
See all 32 naturalized citizens serving in Congress in 2026 — their parties, states, birth countries, and whether those countries extend the same rights to non-native-born residents.
View Member Directory →How naturalized citizens reach the US Congress
A naturalized US citizen is someone who was born outside the United States and later acquired US citizenship through the legal naturalization process — typically a multi-year path involving lawful permanent residence, a background check, an English and civics test, and an oath of allegiance. Once naturalized, that citizen has virtually all the rights of a native-born citizen, with one narrow exception: they cannot be elected President or Vice President, a restriction found in Article II of the Constitution. They can, however, serve in every other federal elected office — including the US Senate and US House of Representatives.
The seven-year and nine-year citizenship requirements (House and Senate respectively) are the only birthplace-adjacent constraints in Article I. Beyond that, the Constitution places Congress on the same footing for naturalized and native-born citizens alike. The result is that foreign-born members have been a feature of Congress from the very first session onward: the 1st Congress itself included naturalized citizens born in Ireland and Switzerland. Every Congress since has included at least some naturalized members, although the total at any given moment rarely exceeds a few dozen.
What “non-citizen voting rights” means in the birth-country columns
Naturalization is one path for a non-citizen to gain full political rights. But many countries never require someone to give up their birth citizenship at all — instead, they extend some category of voting rights to long-term foreign residents. The Commonwealth tradition (UK, Ireland, Canada historically, New Zealand) is the most generous: qualifying Commonwealth citizens can register and vote in national elections on roughly equal terms with citizens of the host country. The European Union model is more restrictive: EU citizens can vote in local and European Parliament elections in any EU member state, but national elections remain citizen-only.
The rest of the world is more restrictive still. Most countries reserve the vote strictly for their own citizens, at all levels of government. That is the norm this tracker measures members against. A member who was born in a country that bans non-citizen voting is, in effect, a one-way democratic exchange: the US welcomed them into its legislature, but the same type of welcome would not have been extended in reverse.
How the data is built and maintained
Member data is compiled from the Biographical Directory of the United States Congress, official chamber biographies, and the public records associated with each member's federal elections. Birth countries are reported as the country of birth at the time — this matters historically for members born in places like “Bohemia” or “Austria-Hungary” that no longer exist as political entities. Voting-law categorizations are drawn from each country's electoral commission, its constitution, and recognized comparative-democracy indices. Laws change; the tracker is refreshed periodically, and the most recent refresh date is shown at the top of this page.
For the full methodology, classification definitions, data sources, and an overview of the tech stack, see the about page.