The Cocagne River flows through Kent County in southeastern New Brunswick, draining into the Northumberland Strait and ultimately the Gulf of Saint Lawrence ecosystem. The watershed occupies the coastal plain of eastern New Brunswick's lowlands, where the terrain slopes gently toward the sea, with elevations ranging from sea level to approximately 150 meters above sea level. This relatively flat geography gives the river a slow to moderate gradient as it winds through agricultural and forested landscapes before emptying into Cocagne Bay and the Northumberland Strait. The river system includes the main stem as well as tributaries such as the Northwest Branch Cocagne River, together forming a watershed that supports a diverse mix of freshwater and estuarine fish species.