California State Route 54

State Route 54
SR 54 highlighted in red
Route information
Maintained by Caltrans and San Diego County
Length	14.212 mi[1] (22.872 km)
Existed	1961–present
Western section
West end	I-5 in National City
Major intersections	I-805 in National City
East end	SR 125 near Spring Valley
Eastern section
West end	SR 94 in Rancho San Diego
East end	El Cajon city limit
Location
Country	United States
State	California
Counties	San Diego
Highway system
State highways in California Interstate US State Scenic History Pre‑1964 Unconstructed Deleted Freeways
← SR 53 → SR 55

State Route 54 (SR 54) is a state highway in the U.S. state of California that consists of two segments in San Diego County. The westernmost part of the highway is known as the South Bay Freeway, beginning at Interstate 5 (I-5) in National City and running along the Sweetwater River before ending at the intersection with SR 125 and Jamacha Boulevard near Spring Valley. SR 54 then resumes at SR 94 in Rancho San Diego as an undivided highway that leads to the city limits of El Cajon. County Route S17 (CR S17) connects the two portions of the highway; the center portion of SR 54 was never constructed.

The first section of the freeway opened in 1963, east of I-805. The extension of the freeway west to I-5 was delayed to coincide with the construction of the Sweetwater River flood channel. While construction started in 1984, a court stopped the process for a few years, and this portion was not complete until 1992. The final section of freeway, which was upgraded from an expressway, opened in 2007, to coincide with the extension of SR 125 south to Otay Mesa.