The health of both Gallatin and his wife declined in the late 1840s, and Hannah died in May 1849. On August 12, 1849, Gallatin died in Astoria, now in the Borough of Queens, New York at age 88. He is interred at Trinity Churchyard in New York City. Prior to his death, Gallatin had been the last surviving member of the Jefferson cabinet and the last surviving senator from the 18th century.