inter-state
The word you're looking for is "interstate," which means existing between states or involving two or more states.
international
interstate
An Olympiad was an Ancient Greek word for contests between city states. This later became known as the Olympic Games
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'United' is the adjectival version of the word 'Union'. In the Civil War, the United States, temporarily minus the Confederate states, was known as the Union.
Perhaps 'extradition' is the word you're looking for.
The word is contiguous. The 48 contiguous states are the states located on the North America continent that are between Canada and Mexico.
The prefix inter- means between or among. One common word for this prefix is international.
"Intra" means within or inside, so "interstate" refers to something that occurs between or connects different states.
The Spanish word for states is "estados".
No states are in between