Washington and Idaho 
But Eastern Washington is simply outvoted by the Liberal Seattle Conurbation… where there no moves afoot for the Eastern half of the state to form its own state in the union? If so, what’s become of them?
Aside from that Florida and Alabama, Maryland and West Virginia, Iowa and Nebraska, New Mexico and Oklahoma.
Washington and Idaho is the best answer.
The "secessionist" movement was like almost all others (for breaking up a state). It was not serious, never gained a serious amount of support, never really organized, and never found any success.
With the odd exception of West Virginia, states do not and probably never will break up.
