These numbers are assigned by the Florida Department of Transportation (FDOT): Concurrencies include US 98 in Pensacola, US 331 in DeFuniak Springs, US 221 in Greenville, US 301 in Baldwin, and US 1 in Jacksonville.

US 90 itself moves onto hidden SR 10A where it narrows back down to two lanes and then takes a turn to the southeast, still keeping Mobile Highway as the street name.

The road then crosses a body of water known as Bayou Marcus Creek which leads to Crescent Lake, the southwest corner of which is flanked by the Osceola Municipal Golf Course.

Four blocks later, the US 90/98 concurrency ends at the intersection with SR 289, where US 98 turns south towards the Pensacola Bay Bridge and runs along the coast of the Gulf of Mexico toward Perry, Lakeland, and Palm Beach, while US 90 continues along Cervantes Street.

After another random series of local streets, residences and parks, US 90 approaches a signaled intersection with Langley Avenue, which is across the street from a wayside for Chimney Park along Red Bluff, the site of the former Hyer-Knowles Planing Mill, which was destroyed by Confederate General Braxton Bragg as part of an attempt to prevent the factory from falling into Union hands.

The first community it runs through is Holt, where it moves slightly further away from the railroad tracks at the intersection of Cooper Lane, and then encounters CR 189, a county extension of SR 189.

It runs in a 2.7 miles (4.3 km) concurrency with CR 189 that shifts back to the side of the tracks before reaching Summertime Drive, which then turns north onto Galliver Cutoff to meet the state highway it was originally part of.

Shortly after crossing the county line, US 90 continues to carry the name "Old Spanish Trail" where it enters the community of Bottle Branch and serves as the northern border of Eglin Air Force Base, although some private property occasionally can be found.

The concurrency and the parallel suffixed route end when CR 181 turns north onto Pine Street, and the alignment of US 90 shifts back towards the east.

But just as it briefly runs direct east, it turns southeast again, as it approaches the George L. Dickerson Bridge over the Choctawhatchee River, and thus the Holmes-Washington County Line, upon which it immediately enters the Town of Caryville, maintaining the street name "Old Spanish Trail."

Shortly after the embankment for this bridge ends, the road has two other local intersections before encountering the southern terminus of CR 179, which leads north to Pittman.

Few locations along this segment are of any note, other than a one-lane dirt road named Ray's Place that leads across the tracks to Vosika's Airport.

However, just east of the site of the former Hulaw L&N Railroad Station, US 90 becomes the northern terminus of State Road 277, and then turns into a four-lane undivided highway once again.

This alignment ends as it curves back to the southeast and approaches the last landmark along US 90 in Jackson County, the Apalachee Correctional Institute, a massive prison farm.

The CSX Tallahassee Subdivision which began in Chattahoochee and carried the Amtrak Sunset Limited approaches US 90 south of there in Saint John running entirely along the southwest side.

The tracks begin to move away from US 90/SRs 12/65, but almost comes back just before the intersection with CR 274 before entering Quincy where the multiplex becomes West Jefferson Street.

Officially leaving the historic district east of Love Street, the road passes by a Sheriff's office and the Eastern Cemetery turning southeast again, just before it leaves the city and becomes a four-lane divided highway, but it clings to the name "East Jefferson Street" until just before the Gadsden Medical Center complex.

Just before entering the capital completely, it intersects State Road 20, which joins SR 10 as an additional hidden route, later becoming West Tennessee Street.

The road re-enters Jefferson County again after crossing a causeway over the southern end of Lake Miccosukee and is named West Washington Street.

The official point where US 90 skirts the border with Monticello is near the Crooked Creek housing development, although most of the rural surroundings continue, as it enters the rest of the city.

Another NRHP-listed site on US 90 is the Perkins Opera House on the south side between Mulberry Street and the traffic circle with US 19 which contains the Jefferson County Courthouse in the center, and itself is part of the Monticello Historic District.

In the City of Madison itself US 90 is named Base Street, which becomes a four-lane undivided highway between Southwest Captain Brown Road and College Loop, both of which were part and all of former US 90 respectively.

The historic Wardlaw-Smith House is on the northwest corner of US 90 and North Washington Street, which is also where the concurrency with State Road 53 begins, as well as the accompanying Florida Short Route, and Lone Star Trail.

After leaving Osceola National Forest just west of CR 250A, it passes Olustee Battlefield Historic State Park, and then has one final interchange with I-10 at Exit 324, running north of the interstate where it will remain for the duration of its journey.

This concurrency may disappear if the Florida Department of Transportation decides to build the proposed Baldwin Bypass around the western edge of town.

[14] Immediately after another railroad crossing with the CSX Callahan Subdivision, both US 90 and 301 narrow down to two lanes at the east end of this concurrency, and then US 90 re-enters Jacksonville.

A large railroad wye does exist at the eastern edge of this underpass and a moderate intersection can be found east of there with the northern terminus of SR 103, which becomes an unmarked city street north of the road.

After passing by Forestry Tower Park, and then intersecting St. John's Bluff Road, it gains access to Interstate 295 that it couldn't have in western Jacksonville, albeit with a single-point urban interchange.

The Southbank section of Hogan Road between Parental Home Road and the South bank of the St Johns River downtown was renamed Beach Boulevard and added to the new section, thus allowing the new Beach Boulevard to exist under one name from the South bank of the St Johns River, all the way out to the Atlantic Ocean.

Routes by the Florida Department of Transportation was stopped when the state could no longer use Federal funds to replace the signs with anything but the standard black-and-white version.