Pre-1964 Legislative Route 3 (California)

State Route 99
Golden State Highway
SR 99 highlighted in red
Route information
Defined by
Maintained by Caltrans
Length:	424.85 mi (683.73 km) (includes unsigned overlap with US 50 and I-5)
Existed:	1928 as US 99, 1964 as SR 99 – present
Major junctions
South end:	I-5 near Wheeler Ridge
	SR 58 in Bakersfield SR 41 in Fresno SR 108 / SR 132 in Modesto SR 120 in Manteca SR 4 in US 50 / I-80 Bus. in Sacramento SR 20 in Yuba City
North end:	SR 36 near Red Bluff
Location
Counties:	Kern, Tulare, Fresno, Madera, Merced, Stanislaus, San Joaquin, Sacramento, Sutter, Butte, Tehama
Highway system
State highways in California Interstate U.S. State Pre-1964 History Unconstructed Deleted Freeway Scenic ← US 99 US 101 →

State Route 99 (SR 99), commonly known as Highway 99 or, simply, as 99 (without any further designation), is a north–south state highway in the U.S. state of California, stretching almost the entire length of the Central Valley. From its southern end at Interstate 5 (I-5) near Wheeler Ridge to its northern end at SR 36 near Red Bluff, SR 99 goes through the densely populated eastern parts of the valley. Cities served include Bakersfield, Delano, Tulare, Visalia, Kingsburg, Selma, Fresno, Madera, Merced, Modesto, , Sacramento, Turlock, Yuba City, and Chico.

The highway is a remnant of the former Mexico to Canada U.S. Route 99 (US 99), which was decommissioned in 1972 after being functionally replaced by I-5 for long-distance traffic. Almost the entirety of the roadway from Wheeler Ridge to Sacramento has been upgraded as of January 2016 to a freeway at least four lanes wide, and Caltrans plans to further upgrade the segment to a minimum width of six lanes and also bring it into compliance with Interstate Highway standards, as a parallel route to I-5 for Los Angeles–Sacramento traffic. North of Sacramento, the road ranges from a rural two-lane road to a four-lane freeway.