Asteroids primarily originate from the asteroid belt, which is located between the orbits of Mars and Jupiter. This region contains numerous rocky bodies that never coalesced into a full planet due to the gravitational influence of Jupiter.
Additionally, there are also some asteroids that come from the Kuiper Belt, which is located beyond the orbit of Neptune and is home to many icy bodies and small celestial objects.
The Oort Cloud is a theoretical region far beyond the Kuiper Belt, believed to be the source of long-period comets, but it is not typically associated with asteroids.
In summary, the primary source of asteroids is the asteroid belt.