The data below are from a body of work which has been published as "A Census of Ireland, circa 1659" by the Irish Manuscripts Commission (Seamus Pender, editor). It is not actually a "Census", as we think of the word today. It lists the totals of the Irish population, as well as the English/Scottish population. It also gives totals for those of the "principall Irish names". Finally it gives a list of the "tituladoes", which are those who owned property. This survey was compiled in preparations for the mass land confiscations which occurred under Cromwell, during the 1660s. Some scholars believe it was compiled by Petty's men, while they were preparing the Down Survey Maps. When the manuscript was rediscovered in 1864, it was given the name "census", by which it has been known since. There are a number of counties and baronies for which no returns have survived, if they existed (for the Ulster region, County Tyrone is missing). While it has a number of critics due to its shortfalls, the fact that this historic record exists today is a considerable virtue in itself. While we can't identify individual forenames of Ó Dochartaighs from it, we can obtain an estimation of the population and distribution of those bearing the surname. (View the complete "Census" at irishmanuscripts.ie. Learn more at John Grenham, Irish Central)
"Inhabitants" from the 1659 "Census"