In prehistoric time, as much as sixty percent of the land that is now Georgia was covered by ocean. When the ocean receded, it left a mostly flat land that we now call the Coastal Plain. The area where the prehistoric ocean’s shoreline lay - a region about twenty miles across - is called the Fall Line. It separates Georgia’s Coastal Plain from its Piedmont region. Piedmont land is higher in elevation than that of the Coastal Plain, causing rivers that begin in the Piedmont to to gather speed - or “fall” - as they pass through the Fall Line into the Coastal Plain.
The Fall Line was very important in the historical growth of Georgia. Rivers in the Coastal Plain tend to be larger and slow moving - making them navigable by large boats. But when the boats reached the Fall Line, they could go no further, so trading posts developed along the Fall Line, where materials brought up from Coastal Plain rivers could be traded for material from the Piedmont region. Four important cities grew from this development - Augusta (at the Fall Line of the Savannah River), Milledgeville (at the Fall Line of the Oconee River), Macon (at the Fall Line of the Ocmulgee River), and Columbus (at the Fall Line of the Chattahoochee River). Later, as industrialization progressed, the same cities had the advantage of water power from the “Falls” where they were established.
The Fall Line remains a distinctive feature of Georgia’s geography to this day. The four cities (three of which have served as Georgia’s capital at various times) are still vibrant and active centers of Georgia commerce. The unique features of the Fall Line are also an attraction to outdoor enthusiasts; state parks such as High Falls State Park have been established along the Fall Line. You can read more about the Fall Line at the New Georgia Encyclopedia.