The name "Magaguadavic" is a Maliseet / Passamaquoddy term that is believed to translate into "River of Eels".
It rises as an outlet of Magaguadavic Lake in York County, flowing south through a low coastal mountain range called the St. Croix Highlands before emptying into Passamaquoddy Bay, a sub-basin of the Bay of Fundy.
The river has 103 named tributaries and 55 lakes draining a watershed measuring 1,812 km2 (700 sq mi).
One of the tributaries drains Lake Utopia into the river and is formally named "The Canal".
The river passes through the following communities from north to south: * denotes estuary portion There are several bridges and one dam crossing the Magaguadavic River, from north to south: The Canal is crossed by a single bridge: