List of CSX Transportation predecessor railroads is a partial listing of railroads which led to the formation of CSX Transportation (CSXT), one of today's major Class 1 railroads in North America.

NOTE: This is a partial list with reporting marks.

• Atlantic Coast Line Railroad (ACL)
• Baltimore and Ohio (B&O)
• Baltimore and Ohio Chicago Terminal Railroad (BOCT)
• Blue Ridge Railroad
• Chesapeake & Ohio (C&O)
• Chessie System
• Clinchfield Railroad (CRR)
• Louisa Railroad
• Louisville and Nashville (LN)
• Plant System Railroads
• Richmond and Petersburg Railroad
• Richmond, Fredericksburg & Potomac Railroad (RFP)
• Seaboard Air Line Railroad (SAL)
• Seaboard and Roanoke
• Seaboard Coast Line Railroad (SCL)
• Seaboard System Railroad (SBD)
• Virginia Central Railroad
• Western Maryland Railroad (WM)