The Archaeological Museum of Marathon is one of the better regional museums in Attica, occupying a modern building a kilometre from the tumulus. Its collections cover finds from the battlefield and the wider Marathon area, including material from the Egyptian sanctuary at Marathon (Ptolemaic-era), artifacts from the Cave of Pan above the valley, and finds from various Bronze Age and Mycenaean sites in the region.
The ground floor covers the prehistoric period and the immediate archaeological context of the battle, while the upper floor covers later Hellenistic and Roman material. The standout exhibits are directly connected to the battle: the Trophy, votive offerings from Pan's cave, and a display explaining the topography of the fight — how the Athenians ran at the Persian line, which flank broke first, and where the pursuit ended at the sea. The museum is signposted from the main road through Marathon and has its own car park.