A bottoms-up, sourced estimate across 28 countries — counting only the U.S.-born descendants of America's immigrant waves.
Demand-constrained, not eligibility-constrained. Even excluding Mexico and Canada, ~10.5M remain.
U.S.-born, dual-compatible, de-duplicated for people who qualify in more than one country. Range 16–44M.
Documented 2025 registrations — a floor, since most countries publish nothing. ~70% is Mexico, mostly first-generation.
About 4% of the eligible pool. A penetration challenge, not a supply one.
Under ~1% act each year through a broken process. The distance between the people who could reclaim a citizenship and those who do is the opportunity.
38.6M Americans claim Irish ancestry; ~4M actually qualify. We applied that same discipline across 28 countries, counting only U.S.-born descendants who can retain a U.S. passport. “50M qualify” is the optimistic ceiling; ~24.7M is the defensible number.
Four countries account for 82% of the eligible pool.
India, Japan, and Ethiopia are shown as 0 because they bar dual citizenship; OCI and Yellow Card programs are residency, not citizenship.
The largest and most durable pool. A 2021 reform removed the generational limit and recent emigration keeps most descendants close to a Mexican-born ancestor. We count U.S.-born Americans only. The real constraint is obtaining the ancestor's birth record — exactly what we handle.
Read the full Mexico guide →Am I eligible? →The largest new opening. Bill C-3 removed the generational limit; descent re-bases to a Canadian-born ancestor alive in 1947 or later, and most Quebec ‘Grande Saignée’ family lines have one. The constraint is documentation and awareness — not the law.
Read the full Canada guide →Am I eligible? →The grandparent market. Only a fraction of the 38.6M with Irish ancestry qualify — the law reaches a grandparent, not Famine-era great-great-grandparents — but large families multiply into millions of eligible grandchildren. Applications are at record highs.
Read the full Ireland guide →Am I eligible? →The one large Asian pool. U.S.-born children of Filipino-citizen parents are natural-born by descent, and dual citizenship is expressly allowed — a recent, sizable, dual-friendly market.
Read the full Philippines guide →Am I eligible? →Our two-axis engine weighs law permissiveness against emigration recency, anchored to U.S. Census/ACS ancestry, Pew/MPI foreign-born shares, and nationality law as of July 2026.
Download The Hidden Heirs, including full data tables, country breakdowns, the complete methodology, and what the estimate cannot tell you.
Figures are defensible estimates built from public data (U.S. Census/ACS ancestry, Pew/MPI foreign-born shares, and each country's nationality law as of July 2026), with explicit low/base/high ranges. They are research, not legal advice. Eligibility depends on your specific family documents and current law.Our bottoms-up estimate across 28 countries is ~24.7 million U.S.-born Americans (range 16–44M) — counting only those who could obtain a second citizenship and keep their U.S. passport. Ancestry counts are far larger, but ancestry isn't eligibility.
Not necessarily. Each country has generational limits and rules — e.g., Ireland generally requires an Irish-born grandparent; Italy tightened to two generations in 2025. That's why the eligible number (~24.7M) is a fraction of the ancestry number.
Mexico, Canada, Ireland, and the Philippines together are ~82% of the eligible pool. Canada's Bill C-3 (Dec 2025) added millions.
For the countries in our estimate, yes — we only count dual-compatible paths. A few countries (India, Japan, Ethiopia) bar dual citizenship and are excluded.
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Heritage Passport Research · July 2026
Figures are defensible estimates built from public data (U.S. Census/ACS ancestry, Pew/MPI foreign-born shares, and each country's nationality law as of July 2026), with explicit low/base/high ranges. They are research, not legal advice. Eligibility depends on your specific family documents and current law.
