U.S. Highway 19 Alternate (US 19 Alt.) is a 37.114-mile (59.729 km) former section of US 19 from St. Petersburg to Holiday, Florida.

Quick Facts Route information, Length ...

U.S. Highway 19 Alternate
US 19 Alternate highlighted in red
Route information
Auxiliary route of US 19
Maintained by FDOT
Length	37.114 mi[1] (59.729 km)
Existed	1951–present
Major junctions
South end	US 92 / SR 687 in St. Petersburg
Major intersections	SR 666 in Seminole SR 686 in Largo SR 60 in Clearwater SR 580 in Dunedin CR 582 in Tarpon Springs
North end	US 19 in Holiday
Location
Country	United States
State	Florida
Counties	Pinellas, Pasco
Highway system
United States Numbered Highway System List Special Divided Florida State Highway System Interstate US State Former Pre‑1945 Toll Scenic
← I-595 SR 595 → SR 597

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Beginning at the intersection of 4th Street North (US 92 and State Road 687 (SR 687) and 5th Avenue North in St. Petersburg, it runs west of US 19 near the Gulf coast passing through the cities of Seminole, Clearwater, Dunedin, and Tarpon Springs before ending at US 19 in Holiday, Pasco County. It is also the unsigned State Road 595 (SR 595) throughout the entire route. It also runs along much of the Pinellas Trail.

US 19 Alt. was established in 1951 when US 19 was realigned from St. Petersburg through Holiday. It hugs the Gulf coast, servicing Seminole, Clearwater, Dunedin, and Tarpon Springs before ending at US 19 in Holiday. Originally, the southern terminus of US 19 Alt. was at US 92/SR 687 in downtown St. Petersburg but was truncated to US 19 in St. Petersburg.^[when?]

As of September 2007, however, signage indicates that US 19 Alt. once again follows US 19's old route all the way to US 92; this original route was numbered and signed as the hidden SR 595 designation of the main route, but the signs are slowly being phased out in favor of US 19 Alt. shields. Both shields are in current use, however, for the time being, with the US 19 Alt. signage on the highway itself, and the SR 595 directional signage at the intersections, including Interstate 275 (I-275) exit 23.

Two extensions of hidden SR 595 exist beyond US 19 Alt. The first one is between US 19 and US 92 in downtown St. Petersburg, though this is being phased out, as signage indicates that US 19 Alt. now ends at US 92 instead of US 19. The other is a brief multiplex with US 19 in Holiday which terminates a block north of the northern terminus of US 19 Alt. in Holiday at Mile Stretch Road. County Road 595 (CR 595) consists of Mile Stretch Road, then takes a sharp left onto Grand Boulevard. Within Holiday and Elfers, the road runs along the right-of-way of a former railroad line before heading to Main Street in New Port Richey, where it secretly makes another left turn before terminating at US 19. CR 595 can be found again between Hudson and Aripeka, where it crosses the Pasco–Hernando county line along the Gulf of Mexico on its way toward Hernando Beach, only to bypass downtown Hernando Beach and terminate once again with US 19, but this time also with the western terminus of CR 574/Spring Hill Drive.