If what I read is correct, Connecticut didn’t formally outlaw slavery until 1849. Only 12 years before the war commenced.
CT actually enacted gradual emancipation before it ratified the Constitution.
Here’s a really interesting timeline.
http://www.fortunestory.org/resources/timeline.asp
Interestingly, in 1686 the killing of a slave was made a capital crime.
Maryland was still a slave state until the war was over. Nowadays everyone will tell you the war was fought to end slavery, but in fact it wasn't.
People say that it was because there had to be SOME REASON why all those people died. Slavery was the ex post facto reason seized upon to justify the carnage.