William Worrall Mayo was an English-born physician and chemist who lived from 1819 to 1911. After studying science in Manchester under John Dalton, he emigrated to the United States in 1846. Throughout his diverse career, he worked as a pharmacist, surgeon, and politician, eventually settling in Rochester, Minnesota. He is most recognized for establishing the private medical practice that his sons, William James and Charles Horace, later expanded into the world-renowned Mayo Clinic.