I think where they’re coming from is that Delaware and Maryland were slave states on the south side of the Mason-Dixon line and West Virginia was part of Virginia until 1863.
I always thought the Mason Dixon line was the official divider.
I haven’t spent much time in MD, but I find WV to be much more culturally southern than a significant part of VA that surrounds DC.
WV, KY and NE TN are difficult to distinguish.
| State | Mass. | N.H. | N.Y. | Conn. | R.I. | Pa. | N.J. | Vt. |
|---|---|---|---|---|---|---|---|---|
| European settlement | 1620 | 1623 | 1624 | 1633 | 1636 | 1638 | 1620 | 1666 |
| First record of slavery | 1629? | 1645 | 1626 | 1639 | 1652 | 1639 | 1626? | c.1760? |
| Official end of slavery | 1783 | 1783 | 1799 | 1784 | 1784 | 1780 | 1804 | 1777 |
| Actual end of slavery | 1783 | c.1845? | 1827 | 1848 | 1842 | c.1845? | 1865 | 1777? |
| Percent black 1790 | 1.40% | 0.60% | 7.60% | 2.30% | 6.30% | 2.40% | 7.70% | 0.30% |
| Percent black 1860 | 0.78% | 0.15% | 1.26% | 1.87% | 2.26% | 1.95% | 3.76% | 0.22% |