From the journals of Messrs. Ingham and Brook, it seems that the work of the Lord prospered during the summer of 1821, at Sheffield, Doncaster (where a chapel had been obtained), Rotherham, Wentworth, Carcroft, Brampton, Bolton, Thorp, Braithwell, Wath, Mexbro', and several other places; and a powerful camp-meeting was held on Mexbro' Common, near Doncaster, on Sunday, June 3rd, by Sheffield and Barnsley Circuits. The day was fine, the excitement in the country great, and the attendance so numerous that several newspapers reported the number of persons present to be 20,000. Mr H. Bourne, in his History of the Connexion, gives a less, and, probably, a more accurate estimate of the number. He says, "This memorable camp-meeting had sixteen praying companies; it was believed that more than 10,000 persons attended and that hundreds were converted to God."
From, ‘The History of the Primitive Methodist Connexion from its origin, by John Petty, 1860, p128http://www.archive.org/details/historyprimitiv01pettgoog