| Date | Event |
|---|---|
| May 01 1866 | Memphis Race Riots Cause Casualties |
| May 02 1866 | Peruvians Fight Off Spanish Fleet |
| May 05 1866 | Memorial Day First Celebrated In New York |
| May 10 1866 | First Modern Romanian King Crowned |
| May 16 1866 | Half Dime Coin Replaced With The Nickel |
| May 31 1866 | Canada And Britain Repulse Fenian Invasion |