Nearly all of the watershed of West Branch Fishing Creek is in the Appalachian Plateau physiographic province's Deep Valley Section.
However, the lowest reaches of it, south of Pennsylvania Route 118, are in the Susquehanna Lowlands section of the ridge and valley physiographic province.

The main rock formations in the area of West Branch Fishing Creek are the Catskill Formation, the Huntley Mountain Formation, and the Burgoon Sandstone.
These formations are all primarily made of sandstone, but also contain conglomerate, shale, and siltstone.
They were formed during the Devonian, Mississippian and Devonian, and the Mississippian, respectively.
The Catskill Formation is mostly found in the lower and middle reaches of the watershed, along the creek and its tributaries.
The Huntley Mountain Formation is found in the upper reaches of the watershed and on some of the streams in that part of the watershed.
The Burgoon Sandstone is found in the watershed, but not on many of its streams.

The soils in the watershed of West Branch Fishing Creek are acidic because of a lack of limestone.

The West Branch Fishing Creek watershed, along with the rest of the upper Fishing Creek watershed, experienced glaciation during the Ice Age.
There is a small moraine in the valley of Hemlock Run, a tributary of West Branch Fishing Creek.
The valley of the creek is a gorge, which is one of the main features of the western part of Pennsylvania State Game Lands #13.
Nearly all of the watershed of West Branch Fishing Creek is in the Appalachian Plateau physiographic province's Deep Valley Section. However, the lowest reaches of it, south of Pennsylvania Route 118, are in the Susquehanna Lowlands section of the ridge and valley physiographic province.
The main rock formations in the area of West Branch Fishing Creek are the Catskill Formation, the Huntley Mountain Formation, and the Burgoon Sandstone. These formations are all primarily made of sandstone, but also contain conglomerate, shale, and siltstone. They were formed during the Devonian, Mississippian and Devonian, and the Mississippian, respectively. The Catskill Formation is mostly found in the lower and middle reaches of the watershed, along the creek and its tributaries. The Huntley Mountain Formation is found in the upper reaches of the watershed and on some of the streams in that part of the watershed. The Burgoon Sandstone is found in the watershed, but not on many of its streams.
The soils in the watershed of West Branch Fishing Creek are acidic because of a lack of limestone.
The West Branch Fishing Creek watershed, along with the rest of the upper Fishing Creek watershed, experienced glaciation during the Ice Age. There is a small moraine in the valley of Hemlock Run, a tributary of West Branch Fishing Creek. The valley of the creek is a gorge, which is one of the main features of the western part of Pennsylvania State Game Lands #13.
West Branch Fishing Creek