25 mars 1781 - Massachusetts: Elizabeth Freeman's Freedom Suit (1781)

Description:

"Elizabeth Freeman (sometimes known as Mum Bett) and another Massachusetts slave successfully sue their master for freedom.

When the Massachusetts Supreme Court used the judge's decision as precedent, it effectively ended legal slavery in the state."

Source:

https://www.nationalgeographic.org/interactive/slavery-united-states/

*exact month & day not known