Events
| Crime/Disasters | In India, the Anglican bishop of Calcutta falls into the Ganges and is swept away and drowned. | 10/06/1866 |
| Crime/Disasters | In New York City, St. Patrick's Old Cathedral, the oldest Catholic church in the city, is destroyed by fire. | 10/06/1866 |
| Campaigns/Elections | In northern England, up to 200,000 working people peacefully demonstrate for franchise reform. | 10/06/1866 |