Here, the stream turns west and flows alongside Pennsylvania Route 307 for several tenths of a mile, crossing it twice.

[1] Mill Run joins the Susquehanna River 215.14 miles (346.23 km) upriver of its mouth.

[5] In the lower reaches of Mill Run, the stream flows over some cascades with a height of 30 feet (9.1 m).

[6] Rock types in the vicinity of Mill Run include green and greenish-gray sandstone, red shale, and others.

[5] The surficial geology in the vicinity of the lower reaches of Mill Run mainly consists of Wisconsinan Till.

[8] The mouth of Mill Run is in the United States Geological Survey quadrangle of Tunkhannock.

[3] The former name appears in a 1946 United States Geological Survey map, while the latter name appears in Israel C. White's 1883 book The geology of the North Branch Susquehanna River Region in the six counties of Wyoming, Lackawanna, Luzerne, Columbia, Montour and Northumberland.

[11] Two concrete tee beam bridges carrying Pennsylvania Route 307 over Mill Run were constructed in Tunkhannock Township in 1925 and are 34.1 and 46.9 feet (10.4 and 14.3 m) long.

A concrete frame bridge carrying the same highway over the stream was built in Tunkhannock Township in 1992 and is 23.0 feet (7.0 m) long.