The railroad's principal purpose was to transport phosphate mined along the Peace River and in the Bone Valley region of Central Florida to the port to be shipped.

At its greatest extent, the Charlotte Harbor and Northern Railway ran from Mulberry to the southern tip of Gasparilla Island, a distance of nearly 100 miles.

From Mulberry, the line proceeded south in a mostly straight trajectory through Bradley Junction, Fort Green Springs, and Ona to Arcadia.

Peter B. Bradley, who created the American Agricultural Chemicals Company, secured the charter for the line in 1905, and renamed it the Charlotte Harbor and Northern Railway.

The Boca Grande port included a 3,000 foot dock for loading large vessels directly from railroad cars.

The trestles contained two steel swing spans built by Virginia Iron Works to accommodate vessel traffic.

[3][page needed] In addition to penetrating more phosphate-rich regions of the state, the extension provided a shortcut for trains traveling between Boca Grande and Tampa.

The brochure claimed that Gaspar had been the most feared buccaneer of his generation during his 40-year career spent ravaging shipping and taking hostages across the Gulf of Mexico to the Spanish Main, that he named most of the islands in the Charlotte Harbor area, and had left an as-yet undiscovered treasure cache in the vicinity of the Gasparilla Inn upon his dramatic death in battle.

[5] The tale was unsupported by any evidence, and Pat Lemoyne, the publicist who wrote it, freely admitted in later years that "there was not a true fact in it" and that it was simply an advertisement written in the style of a romantic adventure to attract the attention of tourists.

[9][page needed] Upon completion of the Fort Myers extension, the Seaboard Air Line operated the former Charlotte Harbor and Northern in three segments.

Increased competition from the Rockport Terminal in the Tampa Bay area led to the closure of the Boca Grande Port in 1979.

Most of the right of way on Gasparilla Island was purchased by a local entrepreneur and converted into the popular Boca Grande Bike Path in 1985, which was the first rail trail in the state of Florida.

A number of bridges along the abandoned route also remain to this day as well, the most notable of which is the causeway over Gasparilla Sound that connected the line to the island.