Colonial Georgia settlers followed the river. From Darien in the coastal lowlands to Fort Barrington 12 miles upriver and on into the wiregrass country, they relied on the Altamaha for transportation, irrigation, and timber. In the vast forests of longleaf pine they cleared small lots, built crude shelter and planted corn, tobacco, sugar cane. Their cattle and hogs roamed freely, grazing on wiregrass, acorns and pine mast.
In the 1770s John and William Bartram's naturalist excursions brought them through the lush Altamaha River watershed, searching for new species of native flora. Camping near Fort Barrington, they identified the overcup oak, 'Quercus lyrata', the Ogeechee lime, and discovered the beautiful "Lost Gordonia" which John named 'Franklinia Alatamaha' after his great friend Benjamin Franklin. The 'Franklinia Alatamaha' is the Bartrams' most famous discovery, and they are credited with saving it from extinction. All Franklinias growing today are descendants of those propagated by the Bartrams at their Philadelphia garden.
For most of the 19th century, The Altamaha was the main artery of trade between middle Georgia and the coast. Flatboats loaded with cotton and corn were floated downriver and then dismantled and sold for lumber. Poleboats carried passengers and freight both ways, and great rafts of the longleaf pine were poled downriver to the Darien and Brunswick lumber mills, destined for ports around the world.