| Name | # Entries |
|---|---|
| Isaacs | 742 |
| Ismail | 634 |
| Ingram | 88 |
| Israel | 70 |
| Immelman | 59 |
| Ibrahim | 57 |
| Iyer | 56 |
| Isaac | 52 |
| Ireland | 50 |
| Irvine | 46 |
| Inglis | 40 |
| Iqbal | 40 |
| Irving | 40 |
| Ingle | 39 |
| Innes | 37 |
| Ismael | 35 |
| Islam | 29 |
| Irwin | 28 |
| Ives | 25 |
| Isherwood | 23 |
| Intyre | 22 |
| Iles | 22 |
| Isaacson | 22 |
| Ingham | 21 |
| Ivey | 20 |
| Ibbotson | 20 |
| Iversen | 20 |
| Imrie | 18 |
| Ivory | 18 |
| Impey | 17 |
| Isbister | 17 |
| Isaks | 16 |
| Isles | 15 |
| Illingworth | 15 |
| Ilunga | 15 |
| Inns | 15 |
| Intosh | 15 |
| Ishmail | 15 |
| Iremonger | 14 |
| Ikin | 13 |
| Izaks | 13 |
| Illing | 13 |
| Issacs | 13 |
| Insley | 13 |
| Inggs | 13 |
| Ince | 13 |
| Ioannou | 13 |
| Inman | 12 |
| Issack | 12 |
| Inder | 12 |
| Illsley | 12 |
| Ireton | 11 |
| Ingles | 11 |
| Itumeleng | 11 |
| Ihlenfeldt | 11 |
| Irish | 11 |
| Isted | 11 |
| Ipsen | 11 |
| Inkster | 11 |
| Immink | 10 |
| Inger | 10 |
| Ivamy | 10 |
| Inkson | 10 |
| Ibell | 9 |
| Idas | 9 |
| Ingley | 9 |
| I | 9 |
| Isemonger | 9 |
| Ihaka | 9 |
| Ilsley | 8 |
| Inch | 8 |
| Imlach | 8 |
| Ivins | 8 |
| Ivanov | 7 |
| Ingpen | 7 |