No visible remains survive, but ancient texts suggest the circuit was some 3,444 feet (1,050 meters) long.
Pausanias, a second-century travel writer, left a detailed account of the track, including its V-shaped starting stalls and their elaborate opening mechanism, as well as its sharp turns, marker posts, and altars.
A circle of stones measuring about 33 feet (10 meters) in diameter also was revealed by the soil survey, which may represent one of the structures Pausanias referred to, Müller said.
The German Archaeological Institute at Athens, which was also involved in the research, is more cautious about the findings.
Wolf-Dietrich Niemeier, the institute's director, cautioned that a direct link has not yet been identified between the recently discovered outlines and the ancient racecourse.
"It could be the hippodrome but I don't think we can say that the hippodrome is 'discovered,'" Niemeier said. "This really has to be confirmed by test excavations and so on."
But the research site is in the "right area" for the hippodrome based on historical evidence, Niemeier said.
Any excavations would first require the permission of Greek authorities, he added.
Hard to Find
Richard Woff of the British Museum in London described the difficulty of pinning down the hippodrome's precise location.
Woff, who isn't connected to the research, said the hippodrome's main structures were most likely its starting stalls and the central barrier that charioteers and riders raced around.
"Apart from that, there probably wasn't a lot to it," he said. "So not only was it buried by silt, there's also the fact that there wasn't much to bury."
The hippodrome events were the most prestigious at the ancient Games, which were under way by 776 B.C.
"The main reason for this was that only the wealthiest people could afford to enter the chariot and horse races," Woff said. "Horses were very much a status symbol in ancient Greece."
While paid professionals would have ridden the horses and chariots, the winning prize went to the owner, he said.
This gave women their only opportunity of claiming an Olympic title since they were barred from either competing in or watching the Games.
"There's evidence a woman did win at the Olympics by doing that," Woff said.
Meanwhile the chariot drivers, who wore long white tunics, are thought to have been the only competitors at Olympia who didn't perform in the nude.
SOURCES AND RELATED WEB SITES