I too am researching the Halfacre part of our family. I am looking for a female Halfacre who married into the McKay family in Tennessee. Probably late 1800 early 1900 timeframe.
Subsequently the McKay's moved to Ohio. William L. McKay, Sr. is the son of the "mother" Halfacre I am looking for.
I am related through marriage and was married to one of the McKay's grandson's.