St. Margaret's Well is located just to the South-east of Holyrood Palace, just off Queen's Drive, to the West of St. Margaret's Loch. Click here for a location map provided by StreetMap.

Good Luck Coins, St. Margaret's Well
There are in fact a number of holy wells on the lower slopes around Arthur's Seat, and immediately behind St. Margaret's Well, slightly up the hillside, is the site of St. David's Well, now filled in. To the East lies the site of St. Anthony's Well, near St. Anthony's Chapel. Out of this group of three wells, though, St. Margaret's is the only one which is still functioning. On the South-west slopes of Arthur's Seat, we also find the Wells o' Wearie.
St. Margaret's Well is set into the hillside, covered by an inner fifteenth century gothic structure apparently based on St. Triduana's Well in Restalrig. In the following photograph, the inner arches can be seen, along with the modern pipe which carries the spring water.

Medieval Interior
However, today, the well is surrounded by a Victorian enclosure, and the original medieval architecture can only be seen by peering through the bars.

Victorian Setting
The well's dedication, of course, is to Edinburgh's own sainted queen, Margaret, famous for her religious reforms in the eleventh century. However, it is likely that this well, along with others in Holyrood and elsewhere, predate the Christian era in its religious significance. Indeed, the common practice of throwing coins into wells such as this for good luck derives specifically from the pagan era.