Hello Laurie, The Flax Growers bounty of 1796 lists William, Andrew, Thomas and Alexander McCorkell in Londonderry. There are few McCorkles (or variations of the name) in Derry in the 1831 census and all are within a spit of Londonderry. Those from Templemore included Andrew, Richard, Thomas, Mary and William all of whom would have been lease holders--eg heads of households. Mary was likely a widow. The census return itself lists the numbers of people in the household and their religion. The John of the later Griffith's valuation could have been the son of one of these McCorkells. Once you find the religion, you could seek the parish records which I am finding are quite prolific for Derry. For the RC's and the Church of Ireland, the Parish is known as Templemore. For the Presbyterians (or Dissenters) there were a number of congregations--Ballyamett, outside of the city of Londonderry and 4 parishes within Londonderry: 1st Derry; 2nd Derry or Strand; 3rd Derry or Great James' Street; and 4th Derry or Carlisle Road. One of the Derry McCorkells who emigrated to the States was a Presbyterian Minister and I would guess that was their religion. There are some McCorkle references in the St Columb Cathedral, Londonderry, the big C of I church there. The earliest reference is to Adam, son of Andrew McCorkle and Mary his wife, baptised on December 14, 1715. The Public Record Office of Northern Ireland microfilmed the 22 volumes of St Columb church records in 1960. These records cover the period 1642-1876. During the 18th century, when Catholics and Presbyterians were persecuted, many Presbyterians had the sacraments performed in Church of Ireland facilities. I would look here for your people. Ron Dale