Ancestry in Nassau County
Data from the Census Bureau's 2008-2010 American Community Survey on how residents identified their ancestry when given a selection of choices. Some towns are not listed because the number of residents surveyed was too small. Also, because this information is based on surveys, there is a different margin of error for each statistic. A complete listing of those margins and of all the data from Long Island, including information from 45 communities with populations of 20,000 or more, is available on this PDF.
| Ancestry | Nassau | Nassau percent | Glen Cove | Glen Cove percent | Hempstead | Hempstead percent | Long Beach | Long Beach percent | North Hempstead | North Hempstead percent | Oyster Bay | Oyster Bay percent |
| Italian | 300,390 | 22.5 | 6,023 | 22.5 | 161,274 | 21.3 | 5,750 | 17.3 | 39,217 | 17.4 | 88,126 | 30.2 |
| Irish | 225,645 | 16.9 | 3,512 | 13.1 | 127,320 | 16.8 | 7,855 | 23.6 | 26,173 | 11.6 | 60,785 | 20.8 |
| German | 141,521 | 10.6 | 2,070 | 7.7 | 77,135 | 10.2 | 3,499 | 10.5 | 18,669 | 8.3 | 40,148 | 13.7 |
| Polish | 71,603 | 5.4 | 1,576 | 5.9 | 35,218 | 4.7 | 2,024 | 6.1 | 14,170 | 6.3 | 18,615 | 6.4 |
| Russian | 56,579 | 4.2 | 644 | 2.4 | 25,873 | 3.4 | 2,012 | 6.0 | 14,183 | 6.3 | 13,867 | 4.7 |
| English | 42,518 | 3.2 | 1,537 | 5.7 | 21,881 | 2.9 | 1,224 | 3.7 | 5,950 | 2.6 | 11,926 | 4.1 |
| American | 41,455 | 3.1 | 333 | 1.2 | 23,858 | 3.2 | 1,205 | 3.6 | 6,683 | 3.0 | 9,376 | 3.2 |
| Greek | 21,292 | 1.6 | 582 | 2.2 | 9,340 | 1.2 | 174 | 0.5 | 4,322 | 1.9 | 6,874 | 2.4 |
| French (except Basque) | 14,329 | 1.1 | 412 | 1.5 | 7,347 | 1.0 | 479 | 1.4 | 2,213 | 1.0 | 3,878 | 1.3 |
| Hungarian | 13,644 | 1.0 | 233 | 0.9 | 6,930 | 0.9 | 485 | 1.5 | 2,849 | 1.3 | 3,147 | 1.1 |
| Scottish | 8,091 | 0.6 | 353 | 1.3 | 3,662 | 0.5 | 149 | 0.4 | 1,494 | 0.7 | 2,433 | 0.8 |
| Swedish | 7,716 | 0.6 | 161 | 0.6 | 3,794 | 0.5 | 245 | 0.7 | 1,089 | 0.5 | 2,427 | 0.8 |
| West Indian (exludes Hispanic origin groups) | 55,765 | 4.2 | 291 | 1.1 | 48,486 | 6.4 | 151 | 0.5 | 4,735 | 2.1 | 2,102 | 0.7 |
| Norwegian | 5,918 | 0.4 | 143 | 0.5 | 3,337 | 0.4 | - | 0.0 | 695 | 0.3 | 1,743 | 0.6 |
| Ukrainian | 5,682 | 0.4 | 153 | 0.6 | 2,714 | 0.4 | 144 | 0.4 | 982 | 0.4 | 1,689 | 0.6 |
| Lithuanian | 3,831 | 0.3 | 136 | 0.5 | 1,847 | 0.2 | 255 | 0.8 | 518 | 0.2 | 1,075 | 0.4 |
| Arab | 7,846 | 0.6 | 33 | 0.1 | 4,287 | 0.6 | 105 | 0.3 | 2,221 | 1.0 | 1,200 | 0.4 |
| Czech | 4,497 | 0.3 | 141 | 0.5 | 2,222 | 0.3 | 304 | 0.9 | 582 | 0.3 | 1,248 | 0.4 |
| Swiss | 2,647 | 0.2 | 51 | 0.2 | 1,355 | 0.2 | - | 0.0 | 380 | 0.2 | 861 | 0.3 |
| French Canadian | 3,322 | 0.2 | 38 | 0.1 | 1,890 | 0.3 | 37 | 0.1 | 455 | 0.2 | 902 | 0.3 |
| Scotch-Irish | 3,232 | 0.2 | 63 | 0.2 | 1,716 | 0.2 | 130 | 0.4 | 564 | 0.3 | 759 | 0.3 |
| Danish | 2,279 | 0.2 | 121 | 0.5 | 1,135 | 0.2 | 17 | 0.1 | 274 | 0.1 | 732 | 0.3 |
| Dutch | 5,184 | 0.4 | 99 | 0.4 | 3,152 | 0.4 | 204 | 0.6 | 707 | 0.3 | 1,022 | 0.3 |
| Subsaharan African | 6,362 | 0.5 | 61 | 0.2 | 5,288 | 0.7 | 16 | 0.0 | 536 | 0.2 | 461 | 0.2 |
| Portuguese | 6,742 | 0.5 | - | 0.0 | 2,617 | 0.3 | 55 | 0.2 | 3,530 | 1.6 | 540 | 0.2 |
| Welsh | 1,796 | 0.1 | 20 | 0.1 | 894 | 0.1 | 19 | 0.1 | 367 | 0.2 | 496 | 0.2 |
| Slovak | 1,510 | 0.1 | 17 | 0.1 | 577 | 0.1 | - | 0.0 | 351 | 0.2 | 565 | 0.2 |