The most important record source, the mid-19th century survey of Ireland known as Griffith's Valuation, is organized by poor law union, parish, barony, and county. But wills probated before 1858 are organized by diocese, and after 1858 by probate district; while parish registers, marriage license bonds, and census records all have an organization linked to one or another of these administrative divisions. To help in identifying the precise location of these divisions, and thus their jurisdiction, Mr. Mitchell has drawn at least three maps for every county. The first county map depicts the civil parishes; the second shows the baronies and dioceses of that county; the third illustrates the poor law unions and the parishes included in the probate districts serving that county.