To keep this headline honest, I treated the IRS data as a proxy, not a perfect headcount. The IRS country tables for Form 2555 track returns claiming the foreign earned income exclusion and related housing benefits, which means the dataset captures an employed, tax-filing slice of Americans abroad rather than every retiree, student, child, or non-filer overseas. The latest country-by-country table currently posted on the IRS international individual tax statistics page is for tax year 2021, so that is the freshest comparable destination breakdown the agency makes publicly available. The table itself also notes that the figures are estimates based on samples, which is another reason to read this as a directional map rather than a perfect census.
Using the downloadable 2016 and 2021 IRS country tables linked on that page, I compared Form 2555 returns by destination and then checked more recent official or near-official population signals where they were available. That method is imperfect, but it is still useful, especially because some obvious expat magnets did not surge in the IRS data. In that comparison, the United Kingdom, Australia, New Zealand, France, and Canada were all flat or down from 2016 to 2021, which is why they do not appear here. The result is not a list of the biggest American populations abroad. It is a narrower look at where the IRS-visible, working slice of Americans overseas appears to have grown the most or stayed especially substantial.
1. Ireland
Ireland is the standout. Comparing the IRS country tables shows Form 2555 returns tied to Ireland jumping from 1,066 in 2016 to 3,468 in 2021, a rise of about 225%. That is the sharpest increase on this list among destinations with a meaningful starting base, and it fits the broader sense that Ireland has become much more visible to Americans looking abroad for work and life changes.
More recent reporting from Ireland points in the same direction. RTÉ reported in August 2025 that new CSO figures showed about 9,600 people arrived from the United States in the year to April 2025, up from 4,900 in the previous 12-month period. The IRS data and the later Irish population signal are not measuring exactly the same thing, but together they make Ireland look like one of the clearest recent growth stories.
2. Spain
Spain looks like one of the clearest current magnets for Americans in Europe. Comparing the IRS country tables shows Form 2555 returns associated with Spain rising from 3,476 in 2016 to 4,123 in 2021. That is not a dramatic percentage spike on Ireland’s level, but it is still a meaningful gain on a much larger base.
The broader migration picture points in the same direction. The OECD says emigration of U.S. citizens to OECD countries totaled 104,000 in 2023, and about 13% of that group went to Spain, the highest share among OECD destinations listed in that country note. That does not make the IRS and OECD figures interchangeable, but it does reinforce the idea that Spain has become one of the most active destinations in the current American-abroad picture.
3. Germany
Germany makes the list less because of a flashy percentage jump and more because its base is so large. Comparing the IRS country tables shows Form 2555 returns tied to Germany climbing from 21,046 in 2016 to 22,683 in 2021. That is only modest growth in percentage terms, but it is still one of the biggest raw return counts anywhere in the dataset.
Germany’s official register data also shows a very large American population already in place. Destatis reports 120,385 U.S. citizens in Germany on 31 December 2024, and its place-of-birth table shows 115,095 of them were born abroad. That makes Germany one of the largest American communities in any country appearing in this IRS-based ranking, even if the growth rate itself is less eye-catching than some smaller entries.
4. Colombia
Colombia is one of the more interesting Latin American cases in the IRS data. Comparing the IRS country tables shows Form 2555 returns linked to Colombia rising from 1,510 in 2016 to 2,590 in 2021, an increase of roughly 72%. That is one of the stronger percentage gains anywhere on this list.
Clean public register-style breakouts for Americans in Colombia are harder to compare quickly than in some OECD countries, which is why the case here rests more heavily on the IRS pattern itself. Even with that caution, Colombia stands out as one of the clearest Latin American growth stories in the Form 2555 data rather than just another country that gets talked about heavily online.
5. Costa Rica
Costa Rica also posted a meaningful jump. Comparing the IRS country tables shows Form 2555 returns tied to Costa Rica increasing from 1,573 in 2016 to 2,308 in 2021, or about 47%. That is not the biggest raw gain in the group, but it is strong enough to separate Costa Rica from plenty of destinations that get constant expat attention without showing the same rise in this tax-return data.
That matters because Costa Rica often appears in relocation conversations for lifestyle reasons first. The IRS pattern suggests the country was also seeing a real increase in the employed, filing slice of Americans abroad, not just a lot of online chatter. In a list built around this narrower proxy, that is enough to keep Costa Rica comfortably in the discussion.
6. Norway
Norway is smaller in absolute size than Germany or Spain, but the trend is still notable. Comparing the IRS country tables shows Form 2555 returns for Norway rising from 2,013 in 2016 to 2,681 in 2021, a gain of about 33%. That gives Norway a visible and credible place in the IRS data even if it is not one of the very largest destinations by raw total.
It is also the kind of country many readers would not automatically expect to surface in a list like this. That makes the result useful. The IRS pattern suggests Norway is not just a niche curiosity for a few Americans abroad but one of the smaller European destinations where the working, tax-filing footprint still moved meaningfully upward over the period.
7. Denmark
Denmark’s increase is easy to miss if you only look at bigger countries. Comparing the IRS country tables shows Form 2555 returns tied to Denmark rising from 1,179 in 2016 to 1,686 in 2021, which works out to roughly 43% growth. That is a stronger percentage increase than Spain or Germany, even if the absolute numbers are much smaller.
In other words, Denmark does not need a huge raw base to matter in this exercise. It earns its place because the increase is large enough to look real rather than random and because it fits the broader pattern in this list of several smaller European destinations gaining visible ground in the IRS data between 2016 and 2021.
8. Luxembourg
Luxembourg is the smallest entry here, but it may be one of the most dramatic percentage movers. Comparing the IRS country tables shows Form 2555 returns tied to Luxembourg rising from 307 in 2016 to 591 in 2021, close to a doubling. The raw American count is still modest, but the growth rate is strong enough to earn Luxembourg a place in a proxy-based ranking like this.
Official Luxembourg census material adds context more than scale. STATEC says the foreign-born population accounted for 49.3% of Luxembourg’s total population in the 2021 census, which underlines how internationally structured the country already is. That does not tell us the American share by itself, but it helps explain why even a relatively small increase in U.S.-linked IRS returns there feels plausible rather than surprising.
The cleanest takeaway is that the map has shifted. The classic English-speaking defaults do not dominate this IRS-based growth picture the way many people assume, while Ireland, Spain, and several smaller European or Latin American destinations look much livelier. The main caution is simple: this is best read as a measure of where the IRS-visible, employed slice of Americans abroad has grown fastest or stayed especially substantial, not a perfect census of every U.S. citizen overseas.