[Lurking Libertarian]

Maine seceded from Massachusetts, Tennessee seceded from North Carolina, Kentucky seceded from Virginia, Vermont seceded from both New York and New Hampshire.

Each time, with the consent of all states involved and the consent of Congress.

[SeeSharp]

Each time, with the consent of all states involved and the consent of Congress.

Not True. Each of the seceding entities were admitted with the consent of Congress, but only Virginia consented to the secession. And Congress didn't even exist at the time Vermont carved itself out. They threatened to join Canada if they weren't recognized as an independent colony by the Continental Congress, which agreed over the objections of New York and New Hampshire.