State Road 55 (SR 55) is mainly the internal or secret designation of U.S. Route 19 through Florida,[citation needed] although it has appeared on maps and atlases on several occasions.

[citation needed] Very little evidence of SR 55's existence can be found, except in Levy, Dixie, and Taylor counties.

After the intersection with SR 64, US 41-301-SR 55 concludes its journey through Bradenton and crosses the Hernando Desoto Bridge over the Manatee River and enters Palmetto.

Right after an interchange with the northern terminus of US 41 BUS, SR 45 shares the hidden concurrency with US 41, but almost instantly, SR 55 meets another interchange with US 19 in Memphis and moves onto that road, only to join I-275(State Road 93) at Exit 5, where they both use the Sunshine Skyway Bridge.

At Exit 17, SR 55 leaves I-275 and resumes its role as the hidden route along US 19 once again, as it will do throughout most of the west coast of the state.

A block after the eastern terminus of County Road 490A, CR 490 branches off to the east as it heads towards Lecanto.