The Munson Steamship Line, frequently shortened to the Munson Line, was an American steamship company that operated in the Atlantic Ocean primarily between U.S. ports and ports in the Caribbean and South America. The line was founded in 1899 as a freight line, added passenger service in 1919, and went out of business in 1937.
The Munson Steamship Line was founded in 1899 by Walter D. Munson, who built a freight line from New York to Havana into a line that encompassed eastern Cuba, Mexico, and ports on the Gulf of Mexico and operated over 60 freighters, and becoming the largest ocean freight company on the Eastern Seaboard. Walter Munson was succeeded first by his son Carlos, and, later, by his son Frank Munson shortly after the end of World War I. The 3,477 GT Munamar, built by Maryland Steel in Baltimore, became the first passenger liner and was employed on the eastern Cuba route.
Frank Munson, after securing former German steamers seized during the war, began New York–South America service with Moccasin (the ex-Prinz Joachim of the Hamburg America Line) in December 1919. Martha Washington, a former Austro-American Line steamer, and Huron, Aeolus and Callao, all former North German Lloyd steamers, were added to the service by the United States Shipping Board (USSB) soon after.