Donald Campbell McRuer (March 10, 1826 – January 29, 1898) was an American politician from the Republican Party who served as U.S. Representative from California's 1st district from 1865 to 1867. McRuer was born March 10, 1826, in Bangor, Maine.He moved to San Francisco, California in 1851 during the California Gold Rush and became a commission merchant.He was a member of the San Francisco Board of Education in 1859 and 1860. McRuer died January 29, 1898, in Saint Helena, California and is buried in Saint Helena Public Cemetery.