It is classed as a 3rd order stream on the EPA waters geoviewer site.

South Branch French Creek rises in Concord Township of southeastern Erie County, Pennsylvania and flows south towards Corry, Pennsylvania then turns west towards Union City, Pennsylvania.

Many tributaries feed into it on its way to French Creek west of Union City.

South Branch French Creek drains 81.3 square miles of Erie Drift Plain (glacial geology).

The watershed receives an average of 47.7 in/year of precipitation and has a wetness index of 457.08.