One Arm
According to the 2010 census, the township has a total area of , of which (or 99.90%) is land and (or 0.12%) is water. The streams of Bat Run, Batson Drain, Bell Run, Coo Run, Gravel Run, Millville Drain, Mud Run, Number One Arm, Number Two Arm, Pebble Run, Stone Branch, Tail Run and Wind Run run through this township.