The Birch River is a 5.1-mile-long (8.2 km) river in Aroostook County, Maine, in the United States. From the confluence of its North Branch and South Branch (47°01′57″N 68°40′44″W / 47.03255°N 68.6790°W) in the southwest corner of the town of Eagle Lake, the river runs southeast to St. Froid Lake in Winterville Plantation. The lake is drained by the Fish River, a tributary of the Saint John River.