State Road 45 (SR 45) is a major north–south 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.