When Allegheny County was created in 1788, its territory extended to the north and west state lines.
[1] The rest of Pitt Township lay between the Allegheny and Monongahela rivers, from their confluence at Pittsburgh (then an unincorporated village within the township) to Turtle Creek on the Monongahela and Plum Creek on the Allegheny.
[6] The final remnant of Pitt Township, bordering north of Oakland, was annexed by Pittsburgh in 1868.
[6] There had been an earlier Pitt Township in southwestern Pennsylvania prior to the creation of Allegheny County.
Formed in 1771 as part of Bedford County, it was originally bounded on the north by the Ohio and Allegheny rivers and on the south by a line drawn due west from the mouth of Redstone Creek.