It is believed that the original pit was a 'natural' depression in the surrounding area, probably caused by the surface collapsing into an abandoned mine dig below. The fact that the pit does not collect water to this day, probably adds credibility to the truth of this. John Wesley described the pit as being about 50 feet deep and two hundred by three hundred feet across the top.
It is said that up to 2,000 people can be seated comfortably on the grass 'seating' around the sides and it is even claimed that in 1773 Wesley preached to his largest congregation ever, a staggering 32,000.
The first use of Gwennap Pit for preaching was September 6th 1762 and the occasion was marked by John Wesley himself, who wrote: 'The wind was so high that I could not stand at the usual place at [the village of] Gwennap; but a small distance was a hollow capable of containing many thousands of people. I stood on one side of this ampitheatre towards the top and with people beneath on all sides, I enlarged on those words in the gospel for the day Blessed are the eyes which see the things that ye see....hear the things that ye hear.'
After Wesley's death the Pit continued to be used for religious gatherings and the tradition continues to this day - in particular the annual gathering on Whitsun, but also with services all through the summer months.
The 12 circular terraces that form the seats were cut by local miners between 1803 and 1806.