The Miramichi River is a river of eastern North America. Rising at Juniper, New Brunswick, Canada, it flows 217 kilometres through the province of New Brunswick to the picturesque Miramichi Estuary and empties into the Gulf of Saint Lawrence. It has two branches, the Northwestern and Southeastern Miramichi.

The Miramichi region was settled by Acadians after the capture of Louisbourg and by English lumbermen. It is famous world wide for its diverse fishery, though the Atlantic salmon for which it was once known has suffered. Baseball great, Ted Williams was one of the many fans of the river, coming to fish it almost every summer following his retirement from baseball.

The name, possibly one of the oldest recorded Canadian toponyms of Native American origin, may derive from the Innu word for "land of the Mi'kmaq".