Not really. We just have some references to the events there; the tombstone of the playwright Aeschylus boasts that he fought at Marathon, and some old men in the comedy Acharnians by Aristophanes refer to themselves as "Marathon-fighters", but that's pretty much it. There was once a magnificent painting of the battle on the so-called Painted Stoa, a building on the Athenian agora; the travel writer Pausanias saw it in the 2nd century AD and describes it in his work. However, only the foundations of the building remain. Without Herodotos, we would barely know what battle Pausanias was talking about.

In terms of physical evidence, though, the mound raised over the buried Athenian dead (called the soros) is still visible to this day.