State Road 145 runs north from US 90 and State Road 53 in Madison to the Georgia border, where it becomes State Route 31. It is also a short route in Fort Walton Beach between US 98 and State Road 85.

U.S. Route 90 (US 90) in the state of Florida is the northernmost east–west United States Numbered Highway in the state. US 90 passes through the county seats of all 15 counties on its course in Florida, and it is also the road upon which many of the county courthouses are located. It is never more than six miles (9.7 km) from Interstate 10 (I-10) throughout the state. It runs as a two-lane highway through most of the sparsely populated inland areas of the Florida Panhandle, widening to four lanes through and near several towns. The speed limit is 55 mph (89 km/h) for all rural points west of Monticello, and it is 60 mph (97 km/h) on all rural points from where it enters Madison County as far as Glen St. Mary.