Since the publication of The Genesis of Mifflin County, The Pioneers of Mifflin County and The People of Mifflin County, additional data on the military units in the Revolution and early families was found by the author.  This publication includes this information as well as;  a review of early land grants, a list of the township officers (1768-1789), quotations from the notes and journals of three ministers, the 1783 signers of the Big Valley call for a minister, a record of the slaves in Mifflin County, a study of population increases, a discussion of the boundaries of the county, the recollections of James Milliken and a set of fictional letters that tell the history of the county.