The Altamaha River is a major river in the U.S. state of Georgia. It flows generally eastward for from its origin at the confluence of the Oconee River and Ocmulgee River towards the Atlantic Ocean, where it empties into the ocean near Brunswick, Georgia. No dams are directly on the Altamaha, though some are on the Oconee and the Ocmulgee. Including its tributaries, the Altamaha River's drainage basin is about in size, qualifying it among the larger river basins of the US Atlantic coast.
Course
The Altamaha River originates at the confluence of the Oconee and Ocmulgee Rivers, near Lumber City. At its source, the river forms the border between Jeff Davis County to the south and Montgomery County to the north.
It is reportedly the third-largest contributor of fresh water to the Atlantic Ocean from North America. Including its longest tributary (the Ocmulgee) in length calculations, as is standard USGS practice, its length of places it seventh on the list of U.S. rivers entirely within one state, behind only four Alaskan rivers, the Sacramento-Pit River in California, and the Trinity River in Texas. The beginning of the Colorado River of Texas is just within New Mexico. The long Mobile-Alabama-Coosa River system, mostly in Alabama, originates a short distance within Georgia.
The Altamaha River traverses a broad area of low population density with few significant towns or cities along its course. Some cities are along its upper tributaries, such as the Fall Line cities of Milledgeville on the Oconee and Macon on the Ocmulgee.
Bullard Creek Wildlife Management Area occupies the southern floodplain of the river's first few miles, after which the river marks the boundary between Toombs County to the north and Appling County to the south.
On the north side, Toombs County gives way to Tattnall County, in which the Ohoopee River joins the Altamaha. The Big Hammock Wildlife Management Area and Big Hammock Natural Area are located along the Altamaha at the Ohoopee confluence. Big Hammock Natural Area is a National Natural Landmark site, noted for its ecological biodiversity and many rare plant species, including Georgia plume.
Below Big Hammock, the tributary Beards Creek joins the Altamaha from the north, after which the river marks the border between Long County to the north and Wayne County to the south. The Altamaha passes through Griffin Ridge Wildlife Management Area before flowing by Doctortown, near Jesup. A wide and swampy floodplain surrounds the river in this area.
Several miles below Doctortown, Wayne County gives way to McIntosh County on the north side of the river. From this point to the river's mouth, numerous wildlife management areas line the river. The Sansaville Wildlife Management Area lies on the south side of the river, while the Altamaha Wildlife Management Area lies on the north and extends down to the river's mouth at Altmaha Sound. Wolf Island National Wildlife Refuge occupies Wolf Island on the Atlantic coast, north of Altamaha Sound. In its last several miles, the Altamaha River marks the boundary between McIntosh County on the north and Glynn County on the south.
The town of Darien lies just north of the Altamaha River's mouth. Several miles to the south lies the larger city of Brunswick. St. Simons Island lies on the south side of the Altamaha estuary. The estuary of the Altamaha River, where fresh and salt water mix, is about in size, one of the largest intact, relatively undegraded estuaries on the Atlantic coast. The Altamaha River Delta has been designated as a site of regional importance to shorebirds by the Western Hemisphere Shorebird Reserve Network.
Natural history
Although used in the 19th century as a route for commerce between central Georgia and the coast, the river is nearly entirely still in its natural state, and was designated a bioreserve by The Nature Conservancy in 1991.
The Altamaha River flows through a flood plain up to wide, consisting of some of the last remaining hardwood bottomlands and cypress swamps in the American South. As the river approaches the Atlantic Ocean, it becomes a broad estuary. At least 120 species of rare or endangered plants and animals live in the Altamaha River watershed, including 11 species of pearly mussels, seven of which are endemic to the Altamaha.
The river basin also supports the only known example of old-growth longleaf pine and black oak forest in the United States. Other notable species include shortnose sturgeon, Atlantic sturgeon, West Indian manatee, Eastern indigo snake (Drymarchon couperi), greenfly orchid, and Georgia plume.