[GreyFriar]

but he was brought in from another state and was ‘legal’ only after the decision named after him. Slavery was not legal under the Northwest Ordinance, for parts of Minnesota were from the old Northwest Territory and the Missouri compromise. And Minnesota did not become a state until 1858.

[Verginius Rufus]

I think Dred Scott's master was stationed at Fort Snelling, on the far side of the Mississippi River (acquired in the Louisiana Purchase, but in the part where slavery was banned by the Missouri Compromise of 1820). It's right across from the Minneapolis-St. Paul Airport but there were no flights in those days so Dred never had a chance to stow away on a plane.

The Dred Scott decision left Dred a slave but his freedom was purchased not long afterwards.