According to the United States Census Bureau, the township has a total area of 13.2 square miles (34.1 km²), of which 12.9 square miles (33.4 km²) is land and 0.27 square miles (0.7 km²), or 1.95%, is water.
It extends from the Susquehanna River in the northwest to the north slope of Wyoming Mountain in the southeast.

Its villages include Hilldale, Hudson, Llewellyn Corners (also in Bear Creek Township), Midvale, Plains, Plainsville, Port Bowkley, and Westminster.

Plains Township's numbered routes include I-81, PA 115, PA 309, and PA 315.
I-476 crosses the eastern portion of Plains Township.
Main Street and River Street cross the populous northwestern portion of the township between Wilkes-Barre and Jenkins Township.
The southern and eastern sections of the municipality are scarcely populated.
This region of the township is mostly made up of forested mountains.
According to the United States Census Bureau, the township has a total area of 13.2 square miles (34.1 km²), of which 12.9 square miles (33.4 km²) is land and 0.27 square miles (0.7 km²), or 1.95%, is water. It extends from the Susquehanna River in the northwest to the north slope of Wyoming Mountain in the southeast.
Its villages include Hilldale, Hudson, Llewellyn Corners (also in Bear Creek Township), Midvale, Plains, Plainsville, Port Bowkley, and Westminster.
Plains Township's numbered routes include I-81, PA 115, PA 309, and PA 315. I-476 crosses the eastern portion of Plains Township. Main Street and River Street cross the populous northwestern portion of the township between Wilkes-Barre and Jenkins Township. The southern and eastern sections of the municipality are scarcely populated. This region of the township is mostly made up of forested mountains.
Plains Township, Luzerne County, Pennsylvania