Alas, NOT actually. For example:

* Slavery was abolished in MA as the result of a 1783 court ruling.

* Under PA act of 1780, those born before 1780 remained slaves for life, and were not finally freed until 1847. Children born to slave parents after 1780 remained indentured servants, (i.e. slaves) until age 28.

* The Vermont Constitition of 1777 abolished slavery, but in reality slaves were still owned in VT until the mid to late 1830's.

* New Jersey was the last of the Northern states to abolish slavery completely & there were slaves there as late as 1865.