Events in May 1866
| MonMonday | TueTuesday | WedWednesday | ThuThursday | FriFriday | SatSaturday | SunSunday |
|---|
| 3030 April 1866 | 11 May 1866 | 22 May 1866 | 33 May 1866 | 44 May 1866 | 55 May 1866 | 66 May 1866 |
| 77 May 1866 | 88 May 1866 | 99 May 1866 | 1010 May 1866 | 1111 May 1866 | 1212 May 1866 | 1313 May 1866 |
| 1414 May 1866 | 1515 May 1866 | 1616 May 1866 | 1717 May 1866 | 1818 May 1866 | 1919 May 1866 | 2020 May 1866 |
| 2121 May 1866 | 2222 May 1866 | 2323 May 1866 | 2424 May 1866 | 2525 May 1866 | 2626 May 1866 | 2727 May 1866 |
| 2828 May 1866 | 2929 May 1866 | 3030 May 1866 | 3131 May 1866 | 11 June 1866 | 22 June 1866 | 33 June 1866 |