Ceres is located in the asteroid belt between Mars and Jupiter. It's not really "by" any specific planet, as it's in a region with many other asteroids.

However, here's what you can say about Ceres' location:

* Nearest planets: Mars is the closest planet to Ceres, followed by Jupiter.

* Orbital distance: Ceres' orbit is not perfectly circular, but it generally stays between 2.5 and 3 astronomical units (AU) from the Sun. This puts it about 1.5 AU from Mars at its closest point and 4 AU from Jupiter at its farthest.

* Asteroid belt: Ceres is the largest object in the asteroid belt, which is a region teeming with millions of smaller asteroids and rocky bodies.

So, while it's not "by" a specific planet, Ceres is the largest object in a region between Mars and Jupiter.