Which American state is the most Irish? Most people say Massachusetts, or New York. By share of the population it is New Hampshire, where one person in five reports Irish ancestry. By number of people it is California, which is almost at the bottom of the list by share. Here is the map, and how it got that way.
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What is being counted
Every year the U.S. Census Bureau asks a sample of Americans to write down their ancestry. In 2024, 32.4 million wrote Irish: about one American in ten. Readers tracing their own family’s roots can start with our step-by-step Irish ancestry guide. That is what people say about their own families; nobody checks it. It does not include the 2.5 million who wrote Scotch-Irish, which the census counts on a separate line. For every state we use the five-year survey, 2020 to 2024 (table B04006), because it is the only one that covers all fifty.
Most Irish by share of the population
New Hampshire is first, at 20.6%. Massachusetts is second, at 18.6%. Then Vermont, Maine and Rhode Island, each around one person in six. All five are in New England. Pennsylvania is sixth and Delaware seventh. The surprise is ninth: Montana, the highest in the West. At the other end are Hawaii, California and Texas, all at six percent or under.
Most Irish by number of people
California has 2.3 million people of Irish ancestry, more than any other state. New York has 2.1 million, Pennsylvania 1.9, Florida and Texas 1.8 each. Not one state is in both top fives. California is first by number and 50th of 51 by share; New Hampshire is first by share and 32nd by number.
All fifty states and Washington, D.C.
| Rank by share | State | Share reporting Irish ancestry | People | Rank by number |
|---|---|---|---|---|
| 1 | New Hampshire | 20.6% | 286,760 | 32 |
| 2 | Massachusetts | 18.6% | 1,310,139 | 8 |
| 3 | Vermont | 16.8% | 108,493 | 45 |
| 4 | Maine | 16.5% | 229,186 | 36 |
| 5 | Rhode Island | 16.1% | 176,962 | 41 |
| 6 | Pennsylvania | 14.8% | 1,928,283 | 3 |
| 7 | Delaware | 14.8% | 151,161 | 42 |
| 8 | Connecticut | 13.9% | 503,149 | 23 |
| 9 | Montana | 13.5% | 150,953 | 43 |
| 10 | Iowa | 12.8% | 411,367 | 27 |
| 11 | Ohio | 12.3% | 1,459,020 | 6 |
| 12 | West Virginia | 12.3% | 218,888 | 38 |
| 13 | New Jersey | 12.1% | 1,130,177 | 9 |
| 14 | Missouri | 11.8% | 727,902 | 15 |
| 15 | Nebraska | 11.7% | 231,984 | 35 |
| 16 | Wyoming | 11.7% | 68,046 | 49 |
| 17 | Kansas | 11.3% | 332,347 | 30 |
| 18 | Colorado | 11.2% | 656,941 | 19 |
| 19 | Oregon | 11.1% | 471,259 | 26 |
| 20 | Kentucky | 11.0% | 497,366 | 24 |
| 21 | Illinois | 10.6% | 1,342,703 | 7 |
| 22 | New York | 10.5% | 2,087,330 | 2 |
| 23 | Wisconsin | 10.4% | 613,046 | 20 |
| 24 | Indiana | 10.1% | 690,715 | 16 |
| 25 | South Dakota | 9.9% | 90,144 | 46 |
| 26 | Michigan | 9.9% | 999,747 | 10 |
| 27 | Minnesota | 9.9% | 566,539 | 22 |
| 28 | Oklahoma | 9.9% | 397,216 | 29 |
| 29 | Washington | 9.8% | 765,987 | 13 |
| 30 | Alaska | 9.5% | 70,110 | 47 |
| 31 | Idaho | 9.5% | 183,185 | 40 |
| 32 | Tennessee | 9.3% | 660,169 | 17 |
| 33 | Maryland | 9.3% | 577,895 | 21 |
| 34 | Virginia | 9.1% | 793,505 | 12 |
| 35 | South Carolina | 9.1% | 480,662 | 25 |
| 36 | Arkansas | 8.9% | 272,301 | 33 |
| 37 | Arizona | 8.9% | 657,986 | 18 |
| 38 | North Carolina | 8.4% | 903,955 | 11 |
| 39 | Florida | 8.2% | 1,838,284 | 4 |
| 40 | District of Columbia | 8.1% | 55,299 | 51 |
| 41 | Alabama | 8.0% | 404,879 | 28 |
| 42 | Nevada | 7.9% | 252,069 | 34 |
| 43 | Mississippi | 7.4% | 218,954 | 37 |
| 44 | North Dakota | 7.2% | 56,859 | 50 |
| 45 | Georgia | 6.9% | 756,390 | 14 |
| 46 | New Mexico | 6.9% | 146,507 | 44 |
| 47 | Louisiana | 6.6% | 302,335 | 31 |
| 48 | Utah | 6.1% | 207,208 | 39 |
| 49 | Texas | 6.0% | 1,801,243 | 5 |
| 50 | California | 5.9% | 2,301,721 | 1 |
| 51 | Hawaii | 4.7% | 68,302 | 48 |
Where the immigrants landed
The census of 1850 counted 961,719 people in the United States who had been born in Ireland. More than a third of them, 343,111, were in one state: New York. With Pennsylvania (151,723), Massachusetts (115,917) and Ohio (51,562), four states held more than two thirds. In Massachusetts and in New York, about one person in nine had been born in Ireland. New Hampshire had 8,811.
By 1870 there were 1,855,827 Irish-born people in the country, close to the most there would ever be. New York had 528,806, Pennsylvania 235,798, Massachusetts 216,120 and Illinois 120,162: six in every ten between them. California, which had 2,452 in 1850, now had 54,421. In 1900 New York still had 425,553, and Florida had 797.
Why there
The National Park Service puts it plainly: many of the Irish came through the port of New York, and through Boston and Philadelphia. They had left farms, and the work they could get was labouring. Most had sailed from Ireland’s own principal port of emigration, Cobh in County Cork. In 1822, about thirty Irish labourers walked from Boston to a village called East Chelmsford to dig canals and build mills; that village became the city of Lowell. Irish immigrants dug the Blackstone Canal too.
The West: Butte, Montana
Montana had 1,635 Irish-born people in 1870 and 9,436 in 1900. One reason is Butte. In the early 1900s its mines produced nearly a third of the world’s copper, and one of its Copper Kings was an Irishman, Marcus Daly. The Irish were the most prominent of its communities, in neighbourhoods named Dublin Gulch and Corktown. Today, in Silver Bow County around Butte, one person in four reports Irish ancestry.
Counties and towns
New York City has more people of Irish ancestry than any other city, yet they are 4.4% of it. Among the big metropolitan areas, Greater Boston is the most Irish, at almost one person in five; Pittsburgh and Philadelphia come next, at about one in six. The county with the most is Cook County, Illinois. The most Irish large county is Plymouth County, Massachusetts, south of Boston, at 27.6%. In the town of Milton, beside Boston, about one person in three reports Irish ancestry. The highest shares today are in the suburbs, not in the cities. For anyone who wants to go further, our guide on finding your ancestral townland covers the next step.
Three cautions
- This is what people write on a form. Nobody has to prove it, and a person can give two ancestries.
- The old figures count people born in Ireland. Today’s count their descendants, wherever the families have moved since.
- The figures for small towns come from a sample, so treat them as rough.
Figures checked against the Census Bureau’s tables on 14 October 2026.
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Picture credits for the video
Every clip, photograph and print in the video is real.
- St. Patrick's Day parade, New York, 1910. Bain News Service, Library of Congress: Bain News Service, publisher, Wikimedia Commons, Public domain
- Boston, Massachusetts: Sammy Marrco, Pexels, Pexels License
- San Francisco, California: Mey Sam, Pexels, Pexels License
- Philadelphia, Pennsylvania: K, Pexels, Pexels License
- Portsmouth, New Hampshire: Daniel Miller, Pexels, Pexels License
- Effingham, New Hampshire: Jeremy Hardin, Pexels, Pexels License
- Montana: EJ Merl, Pexels, Pexels License
- Newburyport, Massachusetts: James Hamar, Pexels, Pexels License
- Los Angeles, California: Dimitri Baret, Pexels, Pexels License
- Dallas, Texas: Omer Toycu, Pexels, Pexels License
- Miami Beach, Florida: Foster, Pexels, Pexels License
- The State Emigrant Landing Depot, Castle Garden, New York. Print, 1861 to about 1880, New York Public Library: Scan by NYPL, Wikimedia Commons, Public domain
- Bird's-eye view of the city of San Francisco, lithograph, 1868. New York Public Library: Britton and Rey — Lithographer; Snow and Roos — Publisher, Wikimedia Commons, CC0
- The waterfront at Boston, Massachusetts, 1890s. Detroit Publishing Co., Library of Congress: Detroit Publishing Co., publisher, Wikimedia Commons, Public domain
- The Eastern Canal beside the Boott Mills, Lowell, Massachusetts. National Park Service photograph, undated: NPS, Wikimedia Commons, Public domain
- Lowell, Massachusetts: Bernie Ongewe, Wikimedia Commons, CC BY-SA 4.0
- Pawtucket Canal, Lowell, Massachusetts: John Phelan, Wikimedia Commons, CC BY 3.0
- Lowell, Massachusetts, where the Merrimack and Concord rivers meet. Print, between 1840 and 1860, Library of Congress: Popular Graphic Arts, Wikimedia Commons, Public domain
- Blackstone Canal, Uxbridge, Massachusetts: Uxbridge Caddie, Wikimedia Commons, CC BY 2.0
- Butte, Montana: Wikimedia Commons, Wikimedia Commons, CC BY 4.0
- Butte, Montana: Fishinphoto, Wikimedia Commons, CC BY-SA 4.0
- Miners drilling by hand in the Parrot Mine, Butte, Montana, 1900. Photograph by Harry C. Freeman: Harry C. Freeman, Wikimedia Commons, Public domain
- The west slope of the hill at Butte, Montana, 1900. Photograph by Harry C. Freeman: Harry C. Freeman, Wikimedia Commons, Public domain
- Fifth Avenue, New York City: Karma Rayshar, Pexels, Pexels License
- Boston, Massachusetts: Teju, Pexels, Pexels License
- Chicago, Illinois: K, Pexels, Pexels License
- Massachusetts: James Hamar, Pexels, Pexels License
- Boston area, Massachusetts: James Hamar, Pexels, Pexels License
- A sheet of the 1920 census for Kings County (Brooklyn), New York. National Archives: Department of Commerce. Bureau of the Census. 1913-1/1/1972, Wikimedia Commons, Public domain
- New York City: Karma Rayshar, Pexels, Pexels License
- Boston, Massachusetts: Richard Lathrop, Pexels, Pexels License
- Maps and charts drawn by Love Ireland; state boundaries from the U.S. Census Bureau cartographic boundary files (public domain).
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