First Coast Railroad

The line from Yulee north into southern Georgia was built in 1894 by the Florida Northern Railroad. It was an extension of the Fernandina and Jacksonville Railroad north to Savannah, Georgia to connect with the South Bound Railroad. The line from Yulee to Fernandina Beach was completed in 1861 by the Florida Railroad which connected Fernandina Beach with Cedar Key. The Florida Railroad, Florida Northern Railroad, Fernandina and Jacksonville Railroad, and the South Bound Railroad were all eventually absorbed by the Florida Central & Peninsular Railroad by 1893.

In 1900, the Florida Central & Peninsular Railroad became part of the Seaboard Air Line Railroad, and the line into Georgia became Seaboard's main line.

Seaboard Air Line became the Seaboard Coast Line Railroad after merging with the Atlantic Coast Line in 1967. The former Seaboard Air Line mainline was designated as the S Line with this specific segment known as the Everett Subdivision. The route to Fernandina Beach was designated the Fernandina Subdivision. The Seaboard Coast Line became the CSX Corporation in the 1980s. With the former Atlantic Coast Line main line (A Line) being used as the through route in the combined network, CSX abandoned the S Line between Riceboro, Georgia (just southwest of Savannah) and Bladen, Georgia in 1986 and redesignated the remaining track as the Kingsland Subdivision (a designation which remains on the CSX line south of Yulee). Track between Bladen and Seals was removed in 1990.

CSX leased the lines north of Yulee to the First Coast Railroad in 2005. The remaining Seaboard track north of Riceboro is operated by the Riceboro Southern Railway, another subsidiary of Genesee & Wyoming.