USS Massachusetts (1845) was a steamer acquired by the U.S. Navy prior to the American Civil War. She was used by the U.S. War Department as a transport during the Mexican-American War and traveled widely, including transiting Cape Horn several times as part of her official duties on both sides of the Americas. During her years of service she spent most of her time on the west coast of North America.
Massachusetts, a wooden steamer, was built in the shipyard of Samuel Hall, Boston, Massachusetts, under the supervision of Edward H. Delano for Mr. R. B. Forbes in 1845. As an auxiliary steam packet, she helped pioneer commercial steamer service between New York City and Liverpool, England.
She was purchased by the War Department in 1847 and during the Mexican-American War served as a troop transport for the Army. In 1848 she steamed round Cape Horn to San Francisco, California; she was transferred to the Navy at Mare Island Navy Yard 1 August 1849; and commissioned the same day, Lt. L. R. Knox in command.