Rhode Island was the only original state that did not send delegates to the 1787 United States Constitutional Convention.
The convention met in Philadelphia to revise the Articles of Confederation, but its delegates instead drafted an entirely new Constitution. Twelve states sent representatives, while Rhode Island declined to participate. Its leaders were wary of a stronger central government and feared that the convention would reduce state authority.
Rhode Island’s absence did not prevent the Constitution from being written or signed. The final document was endorsed by delegates representing twelve states on September 17, 1787. Rhode Island later became the thirteenth and last original state to ratify the Constitution, doing so on May 29, 1790.
This history is distinct from the question of which states refused to sign. Several delegates from represented states, including George Mason and Edmund Randolph of Virginia, declined to sign the final document. Rhode Island was different because it did not send a convention delegation in the first place.