For America's 250th anniversary, on what date was the U.S. Constitution signed?

For America's 250th anniversary, the U.S. Constitution was signed on September 17, 1787.

Delegates signed the document at the Pennsylvania State House in Philadelphia, now known as Independence Hall. The signing concluded the Constitutional Convention after months of debate over how the new federal government should operate.

Thirty-nine delegates signed the Constitution, while several delegates who attended the convention declined to sign. Benjamin Franklin, then 81, was the oldest signer. George Washington, who presided over the convention, signed as a Virginia delegate.

The signing did not immediately put the Constitution into effect. Ratification by nine states was required, and the document became operational on March 4, 1789. The Bill of Rights was proposed later, in 1789, and ratified in 1791.