What is the name of the largest known asteroid?

The largest known asteroid by mass is 4 Vesta, which makes up about 9 percent of the mass of the entire asteroid belt. The asteroid 2 Pallas is slightly larger by volume, but it is less massive than 4 Vesta.

Originally, Ceres was the largest known asteroid in the solar system. In 2006, the International Astronomical Union addressed a long-standing controversy over celestial bodies by rewriting the criteria necessary to classify an object as a planet or dwarf planet. This decision, which famously demoted Pluto to dwarf planet status, also promoted Ceres from asteroid to dwarf planet. The decision left 4 Vesta and 2 Pallas in close contention for the title of largest asteroid.