Florida State Road 20

State Road 20 (SR 20) is a 358.154-mile-long (576.393 km) east-to-west route across northern Florida and the Florida Panhandle in the United States.

SR 20 starts at SR 85 in Niceville as John Sims Parkway, which travels to Eglin AFB East Gate through Valparaiso as westbound SR 85 and southbound SR 397. SR 20 heads slightly southeast while SR 85 goes north towards Crestview. The road shortly after intersects the southern terminus of SR 285 as it passes by Niceville High School, reducing to four lanes from six lanes. SR 20 continues straight through Niceville before turning more southeast, crossing the C.G. Meigs Bridge over Rocky Bayou, exiting the Niceville city limits and entering Bluewater Bay. 3 miles later, the road intersects SR 293, providing access to Destin via the Mid-Bay Bridge before reducing to two lanes and entering Walton County.

Briefly after crossing the county line, SR 20 continues southeast before turning east into Choctaw Beach, skirting along the Choctawhatchee Bay, as a two lane road. Upon leaving Choctaw Beach, the speed limit increases from 45 mph (72 km/h) to 55–60 mph (89–97 km/h) into Portland, intersecting Eglin Site C-6 before intersecting County Road 83A, a loop road, twice in Freeport. Shortly after the second intersection with CR 83A, the road intersects US 331 Business, which happens to be US 331's old alignment through Freeport. SR 20 shortly after intersects US 331, exiting the town shortly after. Throughout the rest of Walton County, SR 20 does not intersect many roads other than SR 81 in Bruce, continuing eastbound.

SR 20 is very short through Washington County, only intersecting SR 79 in Ebro leading to Panama City Beach/Bonifay. The road runs for 5 miles before straddling the Washington/Bay county line for another 6 miles before veering southeast into Bay County.

Only about a mile after completely going into Bay County, SR 20 intersects SR 77, passing by several lakes for a few miles before turning northeast. The road intersects Blue Springs Road, then turning directly east and running close to the Washington County line, but still entirely in Bay County. After the county line ends, the road heads straight east, intersecting US 231 between Fountain and Youngstown, and then enters Calhoun County.

State Road 20 continues heading straight east before veering southeast, then curving northeast, to finally resume the straight eastward pattern. The road becomes the southern terminus of SR 287 before entering a very short concurrency with SR 73 in Clarksville. Outside of it, the route intersects CR 275 between Clarksville and Blountstown. Through Blountstown, SR 20 is known as Central Avenue, still being a two lane road. The road slightly expands to include turn medians, intersecting SR 71, which allows access to SR 69. Shortly after, the road passes by the county sheriff's office and the courthouse. After Blountstown, the road becomes four lane, crossing the Apalachicola River on the Trammell Bridge into Liberty County.

After crossing the Apalachicola River, the road immediately heads into Bristol, remaining a four lane road through the town, intersecting SR 12 in the process. SR 20 then goes slightly southeast, intersecting Dempsey Barron Rd toward Hosford. The route intersects SR 65 in Hosford, after which the road intersects barely any more important roads in the county until it reaches, and running concurrent to, SR 267 right before crossing the Ochlockonee River into Leon County.

SR 20/SR 267 intersect CR 375 shortly after crossing county lines right before SR 267 splits from SR 20 as Bloxham Cutoff, going to US 98 heading to Perry, bypassing Tallahassee. SR 20, meanwhile, goes northeast, intersecting many rural roads through Fort Braden. The route goes straight east once more through Apalachicola National Forest before intersecting some more small, local roads while encountering a few stop light intersections. Finally, SR 20 enters Tallahassee and meets SR 263/Capital Circle SW and directly after meets SR 366, which heads east as Pensacola Street leading to Stadium Drive, while SR 20 heads north as Blountstown Street. About 1.3 miles later, SR 20 meets US 90/Tennessee Street and turns right into a hidden concurrency. The two roads head southeast along Tennessee St before drifting northeast and then east. After intersecting Stadium Drive, the roads head southeast again, passing along the north side of Florida State University. Heading directly east into downtown, the routes meet US 27/SR 61/Monroe Street, where SR 20 turns right onto these routes into another hidden concurrency, while US 90 continues as Tennessee Street heading east. Routes 20/27/61 run south along Monroe Street until heading east with US 27 along Apalachee Parkway in front of the Florida Capitol building, while SR 61 continues south along Monroe Street. Routes 20/27 head east along Apalachee Parkway out of Tallahassee, intersecting US 319/Capital Circle SE along the way. The two routes remain four laned throughout the rest of Leon County.