High Quality Content by WIKIPEDIA articles! Octoraro Creek is a 22.1-mile-long (35.6 km)tributary of the Susquehanna River, joining it 9 miles (14 km) above the Susquehanna`s mouth at Chesapeake Bay. The Octoraro rises as an East and West Branch in Pennsylvania. The East Branch and Octoraro Creek form the southern half of the border between Lancaster and Chester counties until the creek crosses the Mason-Dixon line. It winds through northwestern Cecil County, Maryland before joining the Susquehanna.