Tithe Applotment Books are so called because the information was originally compiled
in nearly 2,000 hand-written volumes. This data set references the counties that
make up present-day Northern Ireland: Counties Antrim, Armagh, Derry, Down, Fermanagh,
In the original enumeration, each landholder was recorded along with details
about their holdings such as size, land quality and types of crops. The amount
of tithe payable by each landholder was based on all of these factors and calculated
by a formula using the average price of wheat and oats from 1816-23.