Rhode Island was the only original state that declined to send delegates to the 1787 Constitutional Convention.
The convention met in Philadelphia from May to September 1787 to address weaknesses in the Articles of Confederation. Delegates from twelve states attended, although the final Constitution was signed by representatives of only eleven states because New York's Alexander Hamilton was the sole signer from his state and Rhode Island was absent altogether.
Rhode Island's government was wary of a stronger central authority and did not appoint a delegation. The state later became the thirteenth state to ratify the Constitution, doing so on May 29, 1790, after the new federal government had already begun operating.
This fact is separate from the Declaration of Independence, which represented all thirteen colonies. Rhode Island did participate in the revolutionary movement and was one of the original states, but its refusal to attend the Constitutional Convention reflects a later dispute over federal power. That distinction makes the state a useful connection between the founding era and America's constitutional development.