It serves as CSX's main route through a region of Central Florida known as the Bone Valley, which contains the largest known deposits of phosphate in the United States.

[2] Much of the Valrico Subdivision dates back to the early 1900s and was originally operated under the same name by the Seaboard Air Line Railroad, a CSX predecessor.

[3] Though track to Bowling Green was previously operated by the Atlantic Coast Line Railroad, another CSX predecessor.

[4] The Valrico Subdivision is currently CSX's busiest rail line thorough Bone Valley and carries large amounts of phosphate traffic, its main commodity.

[2] The line serves phosphate facilities operated by The Mosaic Company, which was created in 2004 after the merger of Cargill Inc. and IMC Global.

[6] The 47 miles of track that are today the Valrico Subdivision were built incrementally from the late 1800s and early 20th century as the phosphate industry in Bone Valley began expanding.

The line also connected to the Charlotte Harbor and Northern Railway (now the Achan Subdivision) in Mulberry which at the time went as far as Port Boca Grande where a vast majority of phosphate was shipped in the early 20th century.

At Walinwa, the line connected to the Kissimmee River Railway which continued east to Nalaca where it served a turpentine mill.

Seaboard would operate the Cross Florida Limited over the line, which was one of the first rail services to connect Tampa and Miami directly.

[9] When the Fort Myers Subdivision was abandoned north of Homeland and south of Bowling Green in the late 1980s, the remaining track was annexed to the Valrico Subdivision (CSX's CH Spur and the Seminole Gulf Railway south of Arcadia are discontinuous segments of this line).

In 1980, the Seaboard Coast Line's parent company merged with the Chessie System, creating the CSX Corporation.