History of Mifflin County, PA
Hope this is helpful for researchers.The following is an abstraction from the link below.
LOCAL HISTORY: Wayne Township, Mifflin County, PA
CHAPTER VII.
WAYNE TOWNSHIP.
"Colonel William Postlethwait, who settled at Mount Union, and his two half-
brothers, Thomas and Samuel, were the first of the name in the county. They
settled here about 1800. Colonel William had three sons, - William, Thomas and
Joseph. The last two settled on the old Major Irwin property. Thomas and Samuel
Postlethwait settled at the head of Long Hollow, where William Postlethwait now
lives. Samuel, a son of Squire Thomas Postlethwait, lives near Heister's Mill.
"A Thomas Postlethwait married Ellen, a daughter of Samuel Drake. In 1829 there
was a John Postlethwait in Newton Hamilton, who kept the "Logan House;" in 1836
Thomas J. Postlethwait, Jr., Joseph Postlethwait and Samuel D. Postlethwait, who
were carpenters in the same village.
http://ftp.rootsweb.com/pub/usgenweb/pa/mifflin/history/local/mifflin-7.txthttp://ftp.rootsweb.com/pub/usgenweb/pa/mifflin/history/local/mifflin-7.txt