The British loyalists were American colonists who supported Britain during the the American revolution (1775-83). Thousands of British people migrated from America during (and after) the war, providing a significant boost the Canadian population. Most of the immigrants were English speaking, but were of mixed-ethnicities. Many loyalists settled in the Southern Ontario and Maritime regions, contributing to the Anti-Confederation opinion being very popular over there.
Some British loyalists were opposed to Confederation because they felt that they must loyal to the “Mother Country”. Others still remembered the Revolutionary war and its bloodshed and chaos. Such an experience may have left a bad taste in their mouths, and they saw seperation from Britain in a negative light.