Benjamin Grayson Orr (1762–1822) was the fourth mayor of Washington, D.C., elected by the council of aldermen in 1817 and serving for two years. Orr, probably born in Virginia, was a grocer in Georgetown – which in the early 19th century was a separate town from Washington. He moved into the city in 1812 and was elected an Alderman, but resigned one year later and became a supplier to U.S. Army brigades in Ohio and Michigan. He died in 1822 and was buried in Congressional Cemetery.