California State Route 58

State Route 58 (SR 58) is a major east-west state highway in the U.S. state of California that runs across the Coast Ranges, the southern San Joaquin Valley, the Tehachapi Mountains, which border the southern Sierra Nevada, and the Mojave Desert. It runs between U.S. Route 101 near Santa Margarita and Interstate 15 in Barstow. It has junctions with Interstate 5 near Buttonwillow, State Route 99 in Bakersfield, State Route 202 in Tehachapi, State Route 14 near Mojave, and U.S. Route 395 at Kramer Junction. SR 58 also provides access to Edwards Air Force Base. At various points it is known as the Calf Canyon Highway, Carrisa Highway, Bakersfield-McKittrick Highway, Rosa Parks Highway, Westside Parkway, Barstow-Bakersfield Highway, Bakersfield Tehachapi Highway, Kern County Korean War Veterans Memorial Highway, and Mojave-Barstow Highway.

Route 58 is defined as follows in section 358, subdivision (a), of the California Streets and Highways Code:

Route 58 is from:
(1) Route 101 near Santa Margarita to Route 33.
(2) Route 33 to Route 43.
(3) Route 43 to just west of Van Buren Place near Bakersfield.
(4) Mohawk Street near Bakersfield to Route 99.
(5) Route 99 to Route 15 near Barstow via Bakersfield and Mojave.

Due to ongoing freeway construction projects in Bakersfield and unincorporated Kern and San Bernardino counties, the definition has yet to be amended by the legislature and may not accurately reflect current or former rights of way maintained by Caltrans. The definition also omits Route 58's concurrencies with other routes instead of duplicating those segments in those other routes' definitions in the code.

State Route 58 between Santa Margarita and Buttonwillow is a winding mountain road through a thinly populated area. From its westernmost terminus at US 101 near Santa Margarita, a few miles north of San Luis Obispo, SR 58 heads east along the former US 101 (El Camino Real) for one mile. SR 58 then heads east and up the winding mountain road, passing through a thinly populated area and an intersection with SR 229. Alternatives such as SR 46 to the north or SR 166 to the south are recommended, as much of this section of SR 58 is prohibited to truck traffic. However, this section of SR 58 does pass through the Carrizo Plain, which is known for its scenic beauty and geological features, including the San Andreas Fault. SR 58 then takes another winding road before joining with State Route 33 in the small town of McKittrick. SR 33 then splits at the north end of McKittrick before SR 58 then enters another, but brief winding road. SR 58 then proceeds northeast for several miles before changing to an east-west alignment and reaching Buttonwillow. SR 58 then joins with the north-south Interstate 5 (I-5) for a few miles to Stockdale Highway, where it resumes heading east and intersects with State Route 43 before reaching Bakersfield. In Bakersfield, the route follows the Westside Parkway to reach State Route 99 at the West Bakersfield Interchange.

East of SR 99, SR 58 briefly enters expressway status with two at-grade intersections in the Caliente area before resuming freeway status east of Caliente. SR 58 then reaches the Tehachapi city limits and traverses the Tehachapi Pass before dropping out of the Tehachapi Mountains into the Antelope Valley at the town of Mojave. Freeway conditions continue from State Route 14 east of Mojave bypassing North Edwards, Edwards Air Force Base, Boron, and Kramer Junction. Approximately 10 miles (16 km) east of an interchange with U.S. Route 395, SR 58 resumes expressway status with two lanes in each direction until just before reaching the easternmost terminus at Interstate 15 in Barstow.

With the lack of four-lane or greater, divided highways that cross the Sierra Nevada between SR 58 at the Tehachapi Pass and Interstate 80 at Donner Summit about hundreds of miles to the north, I-5 and SR 58 are used by motorists to travel between Northern California and points to the southeast, such as Las Vegas (via I-15) and Interstate 40, without having to face the extreme traffic congestion of greater Los Angeles.

SR 58 is part of the California Freeway and Expressway System, and east of I-5 is part of the National Highway System, a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration. SR 58 is eligible for the State Scenic Highway System, but it is not officially designated as a scenic highway by the California Department of Transportation. SR 58 has several names throughout its length, including the Blue Star Memorial Highway (for its entire length); the Kern County Korean War Veterans Memorial Highway, for the section from SR 184 to the Kern County/San Bernardino County Line; and the Rosa Parks Highway, for the section between SR 99 and SR 184. The Korean War Veterans name honors the approximately 8,120 veterans from Kern County, while the section named for Rosa Parks honors the civil rights activist. The portion of SR 58 from Barstow to Bakersfield is sometimes referred to as the Barstow–Bakersfield Highway.