The running track, also called stadion, after the running event and the distance of the same name, was in the first centuries of the games a simple a rectangular track, running east-west between two low slopes within the sanctuary. The stadion was 600 feet long. Because the foot had a slightly different length in all Greek cities, also the length of the stadion differed. The one at Olympia was 192,28 meter.
About 350 BC, a new running track was constructed, just east of the sanctuary. The track was made level with a layer of clay and covered with a thin layer of sand. Two stone slabs, with parallel lines engraved in them, marked the beginning and the end of the track.
There were no seats; the spectators stood on the slopes surrounding the track. Originally, this was the case at all Greek stadia, but in the Roman period more and more stadia received rows of seats in stone. Because the Olympian stadion never received such stone seats, there was space for more people than at stadia that did have seats, namely for about 40.000 to 45.000 spectators. On the east side, the slope is natural, on the three other sides, it was artificially raised. The slopes recede some three meter in the middle, to allow all spectators to see the spectacle. This feature was copied in the modern Olympic stadion of Athens.
The stadion functioned not only for the running events, but also for throwing the discus and the javelin, for the long jump and the fighting competition. The athletes entered the stadion through a roofed-over entrance.