The plain of Marathon is situated on the east coast of Attica, on the shores of the southern Euripus, at a distance by road of about twenty-four miles from Athens. It is one of those alluvial plains which have been formed by the _débris_ brought down by torrents at the head of a broad bay. This bay is sheltered on the north-east by the long, narrow, rocky promontory of Kynosura, which projects for more than a mile from the general line of the coast. Longitudinally the plain runs from north-east to south-west, having a length of from four and a half to five miles. Its breadth from the shore of the bay to the foot of the hills which surround it is from a mile and a half to two miles. These hills are not, save on the south-west side, very lofty, or very steep; but their surface is of that peculiarly rugged nature characteristic of Greek mountain slopes. At either extremity of the plain is a marsh. That on the north-east is very extensive, reaching from the mountains all but to the sea. That on the south-west is small; but being at the extreme end of the plain where Mount Agrieliki comes within a half or three-quarters of a mile from the coast, it renders the passage from the south along the foot of this hill very narrow. This little marsh, though, of course, much drier in summer than in winter, was not, I should say, traversable in August, 1899; and this, too, after a prolonged period of drought. The interval between the two marshes is a little more than three miles. The interval of ground is traversed near its centre by the torrent known as the Charadra, the bed of which is sufficiently marked to form an appreciable military obstacle. Herodotus’ description of Marathon is noticeable for its absence of topographical detail, and in this respect is in strong contrast with his descriptions of Thermopylæ and Platæa. Topographically speaking, he knows more even of Mykale than he does of Marathon. There is, in fact, no evidence, direct or indirect, of his ever having visited the field; and the absence of all descriptive detail is strong presumptive evidence that he never had done so. This may be simply due to the fact that Marathon, unlike Thermopylæ and Platæa, is not on any of the main roads of Greece; but, as it is only twenty-four miles from Athens, and as Herodotus shows himself peculiarly anxious to give topographical details wherever he is describing events of first-rate importance, it would seem as if he did not regard Marathon as being of so much significance as the Athenians made it out to have been. Of purely physical features he says not a word. Of other details he simply mentions the place of the encampment of the Athenians, the sacred precinct of Herakles, the site of which has been discovered high up that valley of Avlona which leads up among the hills from the south-west verge of the plain.