Peculiar to them unless you count: Delaware, Kentucky, Maryland, Missouri, and West Virginia the slave states who did not secede and where it was legal until the 13th amendment was ratified about four months before the end of the war!!!! The 13th Amendment wasn't ratified till December, 1865, some months after the war ended.
When it did go into effect, it freed slaves only in KY (around 50,000) and DE (around 200).
All other slaves in America (98.75%) had been freed before the war ended either by the Emancipation Proclamation or state action.
That's what I said it was constitutionally legal in those states until the 13th amendment was ratified. The emancipation proclamation freed no slaves in that the states it applied to did not recognize it. It was a propaganda ploy to try and get the slaves to rebel!!!