Bailey Brook is a 4.39 mi (7.07 km) long tributary to West Branch French Creek that is classed as a 1st order stream on the EPA waters geoviewer site.

[3] Bailey Brook rises in Venango Township of eastern Erie County, Pennsylvania and then flows southwest to meet West Branch French Creek near Lowville.

Bailey Brook drains 4.63 square miles (12.0 km2) of Erie Drift Plain (glacial geology).

The watershed receives an average of 46.6 in/year of precipitation and has a wetness index of 423.76.

[5] The watershed is about 54% forested.