Massachusetts
- Maine, which is not connected to Massachusetts by land, was separated from it as a new state in 1820, as one of the provisions of the Missouri Compromise.
- During the abolitionism era some supporters of William Lloyd Garrison sought the secession of Essex County from the state.
- In 1977 a Martha's Vineyard Statehood Support Committee existed, promoting the secession of Martha's Vineyard and Nantucket from Massachusetts largely in response to redistricting which associated the islands with Cape Cod. All three areas are known for their status as oceanfront summer resort and vacation communities.
Read more about this topic: List Of U.S. State Partition Proposals