511 Davia (pronounced /dəˈviːdə/ də-VEE-də) is a large main belt C-type asteroid. It was discovered by R. S. Dugan in 1903. It is thought to be one of the ten most massive asteroids. It is approximately 270–310 km in diameter and comprises a guestimated 0.5% of the total mass of the asteroid belt. It is a C-type asteroid, which means that it is dark in colouring with a carbonate composition.