Which U.S. submarine was the first to carry out a submerged launch of the Polaris missile?

USS George Washington was the first U.S. submarine to carry out a submerged launch of the Polaris missile.

On 20 July 1960, the submarine fired a Polaris A-1 missile while submerged off Cape Canaveral, Florida. The launch demonstrated that a submarine could remain hidden beneath the ocean while delivering a strategic ballistic missile, a major development in Cold War deterrence.

George Washington was the lead boat of the U.S. Navy’s first SSBN class. It entered service in December 1959 and carried 16 Polaris missiles. Its patrols helped establish the submarine-based portion of the United States’ nuclear triad.

USS Ethan Allen is sometimes confused with this event because it conducted the first complete test of an operational Polaris weapons system, including a live nuclear warhead test later in 1960. George Washington, however, made the first submerged Polaris launch.