State Road 66 (SR 66) is a 25-mile-long east–west state highway in Hardee County and Highlands County. Its western terminus is an intersection with US 17 (SR 35) in Zolfo Springs; the eastern terminus is an intersection with US 27-98 (SR 25-700) near . The eastern continuation of SR 66 is eastbound US 98-SR 700 toward Okeechobee and West Palm Beach.