* Within our solar system: Neptune is the farthest planet from the Sun.

* Beyond our solar system: There is no single "farthest" planet since there are countless stars and planets in the vast universe. We discover new planets constantly, and the farthest one is always changing!

To answer your question more specifically, we'd need to know what you're interested in:

* The farthest planet we know of: This changes all the time as we explore space.

* The farthest planet from Earth: This would depend on the positions of Earth and the planet in their orbits.

* The farthest planet that's been directly imaged: Currently, none have been directly imaged.

Let me know what you'd like to know, and I can help you find the answer!