Rhode Island was the only state not represented at the 1787 Constitutional Convention.
The convention met in Philadelphia from May 25 to September 17, 1787. Its stated purpose was initially to revise the Articles of Confederation, but the delegates instead drafted an entirely new Constitution. Rhode Island opposed the convention and chose not to send delegates, reflecting strong concern about centralized federal power.
Delegates from the other twelve states attended in varying numbers. The convention's work produced a document that created a federal system with separate legislative, executive, and judicial branches. It also established a ratification process requiring approval from nine states rather than unanimous consent.
Rhode Island eventually ratified the Constitution on May 29, 1790, becoming the thirteenth and final state to do so. Its delayed ratification meant that the Constitution had already been operating for more than a year under the federal government established in 1789.