After the start of the Civil War, Virginia seceded from the United States and its capital city of Richmond eventually became the capital of the Confederate States.
Sometimes Roman provincial leaders seceded from the Roman Empire as did Posthumous in Gaul or they even established their own empire as Ordinadus in Zenobia did on the fringes of Western Syria.
Welcomed at first the settlers soon wore out their welcome by openly calling for union with the United States. In 1836 settlers seceded from Mexico and declared what they call the Republic of Texas.