State Road 685 (SR 685) is mainly a north–south highway in
Tampa, Florida. From
Dale Mabry Highway in South Tampa, the route follows Henderson Boulevard northeasterly for roughly one mile to
Kennedy Blvd/
SR 60. The remainder of the route is unsigned, but the hidden designation follows Kennedy Boulevard eastward to
U.S. Route 41 Business (US 41 Bus.), at which point it turns north and becomes that highway's secret designation for just over 11 miles (18 km) until the merge with
US 41 near
Lutz.