This is the watershed of the township and from this point the water is drained south, east and west.

[3] The township's early settlers were Germans, who migrated northward from Oley.

[3] Sacony and Beaver Creeks have been a source for power generation of various mills in Rockland Township and surrounding areas.

Rohrbach's Mill in the western section of the township, was destroyed by fire and has not been rebuilt.

[3] Sally Ann Charcoal Furnace, which was built in 1811 and operated until 1879, was also based on the Sacony.

[3] In 1976, Sally Ann Furnace Complex, located in the township, was added to the National Register of Historic Places.

[4] According to the U.S. Census Bureau, the township has a total area of 17.1 square miles (44.2 km2), all land.

Its villages include Boyers Junction, Dryville, New Jerusalem, and Sally Ann.

Rockland has a humid continental climate (Dfa/Dfb) and the hardiness zone is mainly 6b, with some 6a in higher elevations.

Average monthly temperatures in New Jerusalem range from 27.6 °F in January to 71.4 °F in July.