Alluvium and Wisconsinian Outwash area also present, as is bedrock consisting of sandstone and shale.

Marsh Run begins in a small pond in western Fairmount Township, Luzerne County.

It flows west for several tenths of a mile, passing through a wetland and crossing Hynick Road.

The stream continues flowing west, receiving an unnamed tributary from the right after a short distance.

[1] Marsh Run joins Coles Creek 4.48 miles (7.21 km) upstream of its mouth.

[4] Wild trout naturally reproduce in Marsh Run throughout between its headwaters and its mouth.