Foothill Freeway

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Interstate 210 and State Route 210
Foothill Freeway
I-210 highlighted in red; SR 210 in purple
Route information
Auxiliary route of I-10
Maintained by Caltrans
Length	85.31 mi[1][2] (137.29 km) Length includes the entire Route 210.
History	Route proposed 1933 Designated 210 in 1964
Component highways	I-210 from Los Angeles to Glendora SR 210 from Glendora to Redlands
Major junctions
West end	I-5 in Los Angeles
Major intersections	SR 118 in Los Angeles SR 2 in La Cañada Flintridge SR 134 in Pasadena I-605 in Irwindale SR 57 in Glendora I-15 on the Rancho Cucamonga-Fontana border I-215 in San Bernardino SR 330 near Highland
East end	I-10 in Redlands
Location
Country	United States
State	California
Counties	Los Angeles, San Bernardino
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Future State highways in California Interstate US State Scenic History Pre‑1964 Unconstructed Deleted Freeways
← SR 209 → SR 211

The Foothill Freeway is a freeway in the Los Angeles metropolitan area, California, United States, running from the Sylmar district of Los Angeles east to Redlands. The western segment is signed as Interstate 210 (I-210) from its western end at I-5 to SR 57 in Glendora, while the eastern segment is signed as State Route 210 (SR 210) to its eastern terminus at I-10. Under the California Streets and Highways Code, the entire Foothill Freeway is legally referred to as Route 210.

The Foothill Freeway name is a reference to Foothill Boulevard and the San Gabriel Mountains, both of which the freeway runs parallel to for most of its length. The freeway follows the foothills of these mountains, connecting the northeastern suburbs of Los Angeles with the Inland Empire. Historically, the Foothill Freeway spanned multiple numerical designations. Additionally, the I-210 designation has changed routings, previously including a portion of what is now the Orange Freeway (SR 57). East of Pasadena, the Foothill Freeway parallels, and in some parts replaced, the route of former U.S. Route 66.

The portion between I-5 and SR 259 in San Bernardino was up to Interstate Highway standards by 2007, but the eastern segment remains signed as a state route because the portion between SR 259 and I-10 had not met those standards.^[3] On February 26, 2020, construction in each direction took place to complete the standards required. The three-year project added lanes from Sterling Avenue in San Bernardino to San Bernardino Avenue in Redlands. Although construction was completed in September 2023, the eastern end currently remains "Route 210".^[4][5]