So my wife and I are talking about slavery and had a question specifically of the 13 Colonies. It was to my understanding that there was slavery everywhere until the Proclamation. She doesn't think that ALL the colonies had them. Just didn't want to argue all day about this. Thanks in advance!
This is a pretty quick and simple, fact-based question so this response is not going to be too long.
Yes.
All of the "thirteen colonies" which later became the United States had slavery. The first state to abolish slavery was Vermont, which included an anti-slavery provision in their state constitution in 1777. States like Pennsylvania, New York, Massachusetts, Rhode Island, etc. would follow in the next few years. Some of these states abolished slavery outright, but many began programs of "gradual emancipation," where, say, all children born after 1790 to enslaved mothers would be free, after a period of "apprenticeship" lasting into their adulthoods and often not affecting their parents. As a result of New Jersey's incredibly protracted and circuitous gradual emancipation process, there were people enslaved in the state until *1865*!
But another important reality of slavery in colonial America is that it was not evenly concentrated. Northern colonies were societies with slavery. Southern colonies were slave societies. The difference between the former and latter is that slave societies are dependent on slave labor for their core economic life, with a correspondingly higher proportion of the population (at least 20 percent by most arguments) enslaved. Societies with slavery might have large numbers of enslaved workers, but their labor is not the core of economic life. The majority of enslaved people in colonial America lived in Southern colonies and labored on plantations, raising and processing cash crops to be sold by the people who owned them as property. The demographics reflect this. In 1750, the height of slavery as an institution in the colony of Pennsylvania, enslaved workers numbered approximately 6,000 in a population of approximately 120,000, so about five percent of the population. In Virginia in 1790, ought of a population of approximately 732,000, enslaved workers numbered 292,000, approximately forty percent of the state's population.
This dramatic imbalance might play some part in the fact that slavery as practiced in the colonial "North" is not nearly so well-remembered as southern slavery throughout the colonial and antebellum period.