Check this very cool animation of some asteroids orbiting within Jupiter's L4 and L5 lagrange points. The yellow dot at the top is Jupiter, and the fast green on in the middle is Earth. See how huge an area Jupiters L4 and L5 occupy! I assume the main rotating circle of asteroids is the asteroid belt. You can also see the glomming of asteroids around Jupiters L3 as well.
Linked from here.