William Wallace Crapo (May 16, 1830 – February 28, 1926) was a member of the United States House of Representatives from Massachusetts.

William Wallace Crapo was a brother of the Alpha Delta Phi fraternity in his undergraduate years at Yale University.

In 1903, Crapo (pronounced cray-poe) was a founding member and first president of the Old Dartmouth Historical Society, governing body of the New Bedford Whaling Museum.

His mother, Mary Ann (Slocum) Crapo (1805–1875), was a descendant of William Hutchinson (Rhode Island judge) and his wife Anne Hutchinson, daughter of Francis Marbury.

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