The Old Augusta Railroad (reporting mark OAR) is a 2.5-mile long (4.0 km) shortline railroad that runs from the Georgia-Pacific Leaf River Cellulose pulp mill near the Old Augusta Historic Site in New Augusta, Mississippi to an interchange with the Canadian National Railway (CN) between Mahned, Mississippi and New Augusta.

The Interstate Commerce Commission approved common carrier status for the railroad on February 23, 1983.

[2] The railroad was built by Leaf River Forest Products, Inc., which was owned by its parent company, Georgia-Pacific.

[1] The OAR connects to the CN Beaumont Subdivision, which runs between Mobile and Hattiesburg.

As part of the sale, OAR's name was changed to Old Pine Belt Railroad Company, which was a corporate shell that ceased operations on May 7, 2004.