State Road 45 (SR 45) is a major northâÂÂsouth highway extending almost the entire length of the Florida peninsula. It is the mostly unsigned designation from the Florida Department of Transportation (FDOT) for most of the current U.S. Highway 41 (US 41) in the state. The southern terminus of SR 45 is an intersection with SR 90 in downtown Naples; the northern terminus is an intersection with US 441 (SR 25) in High Springs. South of Causeway Boulevard (SR 676) near Tampa, SR 45 is also known as Tamiami Trail.
South and east of Naples, US 41 turns eastward as SR 90 as the Tamiami Trail crosses the Everglades on its way to Miami; north of High Springs, US 41 overlaps US 441 until their split in Lake City (from there US 41 continues to the Georgia border with the hidden SR 25 designation).
State Road 45A (SR 45A) is the Venice Bypass, a segment along US 41 east of Tamiami Trail in Venice, which was originally part of US 41 until 1965 when that segment was redesignated as Business US 41 after the Intracoastal Waterway (ICW) was dredged through Venice by the U.S. Army Corps of Engineers in 1964. The higwhay begins near Shamrock Boulevard in Venice Gardens and terminates at Venetia Bay Boulevard in the Eastgate section of Venice.