Allegheny County was carved from Westmoreland and Washington counties in 1788. At that time seven (7) townships were made in Allegheny County which were Elizabeth, Mifflin, Moon, Pitt, Plum, St. Clair and Versailles.

In the minutes of the court of quarter sessions at the first session after the formation of Allegheny county, Mifflin Township's boundaries are described, "Beginning at the mouth of Street's run, thence up the Monongahela river to the line of the county, and by the said line to the line of St. Clair township."

Mifflin Township was first split in 1828 when a section of it (just about one-half) was taken to form Jefferson Township.

The local histories of our communities may be had by clicking on any of the communities linked to the right.

NOTE: The linked histories are undergoing an extensive rebuilding. Please bear with us as we move ahead with the redesign of the website.