Which of the original 13 Colonies abolished slavery first? Which two Northern States retained slavery until the early 1800's?

Vermont was the first, outlawing slavery in July, 1771.  New York outlawed this "peculiar institution" in 1799, and New Jersey, in 1804, was the last Northern state to officially abolish the practice.  While slavery was on its last legs in the North, however, it was on its way to a rebirth of sorts in the South.  As farms gave way to factories in the North due to industrialization, Eli Whitney's cotton gin made it possible for slaves to separate cotton from the seedpods far more efficiently than before.  Ironically enough, this invention, a product of the Industrial Age, served to cement for Southerners the agricultural way of life supported by slavery.  There was an enormous amount of money to be made selling cotton to the factories of the North and Britain, and for most Southerners, especially plantation-owning ones, any thoughts of abandoning the agricultural way of life to industrialize and "keep up" with the North, dissipated as profits skyrocketed.